1
|
Comparat D, Malbrunot C, Malbrunot-Ettenauer S, Widmann E, Yzombard P. Experimental perspectives on the matter-antimatter asymmetry puzzle: developments in electron EDM and [Formula: see text] experiments. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2024; 382:20230089. [PMID: 38104615 DOI: 10.1098/rsta.2023.0089] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/15/2023] [Indexed: 12/19/2023]
Abstract
In the search for clues to the matter-antimatter puzzle, experiments with atoms or molecules play a particular role. These systems allow measurements with very high precision, as demonstrated by the unprecedented limits down to [Formula: see text] e cm on electron EDM using molecular ions, and relative measurements at the level of [Formula: see text] in spectroscopy of antihydrogen atoms. Building on these impressive measurements, new experimental directions offer potential for drastic improvements. We review here some of the new perspectives in those fields and their associated prospects for new physics searches. This article is part of the theme issue 'The particle-gravity frontier'.
Collapse
Affiliation(s)
- D Comparat
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Paris Saclay, Université Paris-Saclay, Bâtiment 505, 91405 Orsay, France
| | - C Malbrunot
- Physical Science Division, TRIUMF, Vancouver, British Columbia, Canada V6T 2A3
- Department of Physics, McGill University, Montréal, Québec, Canada H3A 2T8
| | - S Malbrunot-Ettenauer
- Physical Science Division, TRIUMF, Vancouver, British Columbia, Canada V6T 2A3
- Department of Physics, University of Toronto, Toronto, Ontario, Canada M5S 1A7
| | - E Widmann
- Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, 1030 Vienna, Austria
| | - P Yzombard
- Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Université, Collège de France, Paris 75252, France
| |
Collapse
|
2
|
Goli M, Bressanini D, Shahbazian S. On the nature of the two-positron bond: evidence for a novel bond type. Phys Chem Chem Phys 2023; 25:29531-29547. [PMID: 37905569 DOI: 10.1039/d3cp03003b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
The nature of the newly proposed two-positron bond in (PsH)2, which is composed of two protons, four electrons and two positrons, is considered in this contribution. The study is done at the multi-component-Hartree-Fock (MC-HF) and the Diffusion Monte Carlo (DMC) levels of theory by comparing ab initio data, analyzing the spatial structure of the DMC wavefunction, and applying the multi-component quantum theory of atoms in molecules and the two-component interacting quantum atoms energy partitioning schemes to the MC-HF wavefunction. The analysis demonstrates that (PsH)2 to a good approximation may be conceived of as two slightly perturbed PsH atoms, bonded through a two-positron bond. In contrast to the usual two-electron bonds, the positron exchange phenomenon is quite marginal in the considered two-positron bond. The dominant stabilizing mechanism of bonding is a novel type of classical electrostatic interaction between the positrons, which are mainly localized between nuclei, and the surrounding electrons. To emphasize its uniqueness, this mechanism of bonding is proposed to be called gluonic which has also been previously identified as the main driving mechanism behind formation of the one-positron bond in [H-,e+,H-]. We conclude that the studied two-positron bond should not be classified as a covalent bond and it must be seen as a brand-new type of bond, foreign to the electronic bonding modes discovered so far in the purely electronic systems.
Collapse
Affiliation(s)
- Mohammad Goli
- School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran.
| | - Dario Bressanini
- Dipartimento di Scienza e Alta Tecnologia, Università dell'Insubria, Como, Italy.
| | - Shant Shahbazian
- Department of Physics, Shahid Beheshti University, Evin, Tehran 19839-69411, Iran.
| |
Collapse
|
3
|
Anderson EK, Baker CJ, Bertsche W, Bhatt NM, Bonomi G, Capra A, Carli I, Cesar CL, Charlton M, Christensen A, Collister R, Cridland Mathad A, Duque Quiceno D, Eriksson S, Evans A, Evetts N, Fabbri S, Fajans J, Ferwerda A, Friesen T, Fujiwara MC, Gill DR, Golino LM, Gomes Gonçalves MB, Grandemange P, Granum P, Hangst JS, Hayden ME, Hodgkinson D, Hunter ED, Isaac CA, Jimenez AJU, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Madsen N, Martin L, Massacret N, Maxwell D, McKenna JTK, Menary S, Momose T, Mostamand M, Mullan PS, Nauta J, Olchanski K, Oliveira AN, Peszka J, Powell A, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Schoonwater J, Silveira DM, Singh J, Smith G, So C, Stracka S, Stutter G, Tharp TD, Thompson KA, Thompson RI, Thorpe-Woods E, Torkzaban C, Urioni M, Woosaree P, Wurtele JS. Observation of the effect of gravity on the motion of antimatter. Nature 2023; 621:716-722. [PMID: 37758891 PMCID: PMC10533407 DOI: 10.1038/s41586-023-06527-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 08/09/2023] [Indexed: 09/29/2023]
Abstract
Einstein's general theory of relativity from 19151 remains the most successful description of gravitation. From the 1919 solar eclipse2 to the observation of gravitational waves3, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating content of the universe. Singularities in the general theory of relativity and the lack of a quantum theory of gravity suggest that our picture is incomplete. It is thus prudent to explore gravity in exotic physical systems. Antimatter was unknown to Einstein in 1915. Dirac's theory4 appeared in 1928; the positron was observed5 in 1932. There has since been much speculation about gravity and antimatter. The theoretical consensus is that any laboratory mass must be attracted6 by the Earth, although some authors have considered the cosmological consequences if antimatter should be repelled by matter7-10. In the general theory of relativity, the weak equivalence principle (WEP) requires that all masses react identically to gravity, independent of their internal structure. Here we show that antihydrogen atoms, released from magnetic confinement in the ALPHA-g apparatus, behave in a way consistent with gravitational attraction to the Earth. Repulsive 'antigravity' is ruled out in this case. This experiment paves the way for precision studies of the magnitude of the gravitational acceleration between anti-atoms and the Earth to test the WEP.
Collapse
Affiliation(s)
- E K Anderson
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C J Baker
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, UK.
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK.
| | - N M Bhatt
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - G Bonomi
- University of Brescia, Brescia and INFN Pavia, Pavia, Italy
| | - A Capra
- TRIUMF, Vancouver, British Columbia, Canada
| | - I Carli
- TRIUMF, Vancouver, British Columbia, Canada
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Charlton
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - A Christensen
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - R Collister
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - A Cridland Mathad
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - D Duque Quiceno
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - S Eriksson
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - A Evans
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - S Fabbri
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Accelerator and Technology Sector, CERN, Geneva, Switzerland
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.
| | - A Ferwerda
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - T Friesen
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | | | - D R Gill
- TRIUMF, Vancouver, British Columbia, Canada
| | - L M Golino
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - M B Gomes Gonçalves
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | | | - P Granum
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - D Hodgkinson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - E D Hunter
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C A Isaac
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | | | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - J M Jones
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - S A Jones
- Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, Groningen, The Netherlands
| | - S Jonsell
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - A Khramov
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Physics, British Columbia Institute of Technology, Burnaby, British Columbia, Canada
| | - N Madsen
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - L Martin
- TRIUMF, Vancouver, British Columbia, Canada
| | | | - D Maxwell
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - J T K McKenna
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - T Momose
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - M Mostamand
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - P S Mullan
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
- Institute for Particle Physics and Astrophysics, ETH, Zurich, Switzerland
| | - J Nauta
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | | | - A N Oliveira
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - J Peszka
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
- Institute for Particle Physics and Astrophysics, ETH, Zurich, Switzerland
| | - A Powell
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - C Ø Rasmussen
- Experimental Physics Department, CERN, Geneva, Switzerland
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Sameed
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Accelerator Systems Department, CERN, Geneva, Switzerland
| | - E Sarid
- Soreq NRC, Yavne, Israel
- Department of Physics, Ben Gurion University, Beer Sheva, Israel
| | - J Schoonwater
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - J Singh
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - G Smith
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - C So
- TRIUMF, Vancouver, British Columbia, Canada
| | | | - G Stutter
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- School of Mathematical and Physical Sciences, University of Sussex, Brighton, UK
| | - T D Tharp
- Physics Department, Marquette University, Milwaukee, WI, USA
| | - K A Thompson
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - R I Thompson
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - E Thorpe-Woods
- Department of Physics, Faculty of Science and Engineering, Swansea University, Swansea, UK
| | - C Torkzaban
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - M Urioni
- University of Brescia, Brescia and INFN Pavia, Pavia, Italy
| | - P Woosaree
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| |
Collapse
|
4
|
Swann AR, Green DG. Maxwellianization of Positrons Cooling in CF_{4} and N_{2} Gases. PHYSICAL REVIEW LETTERS 2023; 130:033001. [PMID: 36763379 DOI: 10.1103/physrevlett.130.033001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 05/24/2022] [Accepted: 10/28/2022] [Indexed: 06/18/2023]
Abstract
Positron cooling in CF_{4} and N_{2} gases via inelastic vibrational and rotational (de)excitations is simulated, importantly including elastic positron-positron collisions. For CF_{4}, it is shown that rotational (de)excitations play no role on the experimental timescale, and further, that in the absence of positron-positron collisions, cooling via excitation of the dipole-active ν_{3} and ν_{4} modes alone would lead to a non-Maxwellian positron momentum distribution, in contrast to the observations of experiment. It is shown that the observed Maxwellianization of the distribution may be effected by positron-positron collisions and/or cooling involving the combination of the dipole-inactive ν_{1} mode with the dipole-active modes. For N_{2}, rotational excitations alone are sufficient to Maxwellianize the distribution (vibrational effects are negligible).
Collapse
Affiliation(s)
- A R Swann
- School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, United Kingdom
| | - D G Green
- School of Mathematics and Physics, Queen's University Belfast, University Road, Belfast BT7 1NN, United Kingdom
| |
Collapse
|
5
|
Uribe AJ, Cridland Mathad A, Lacy JH, Pinder J, Willetts R, Verdú J. High frequency properties of a planar ion trap fabricated on a chip. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:083202. [PMID: 36050058 DOI: 10.1063/5.0091745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 07/16/2022] [Indexed: 06/15/2023]
Abstract
We report on the measurement of the high frequency properties of a planar Penning ion trap fabricated on a chip. Two types of chips have been measured: the first manufactured by photolithographic metal deposition on a p-doped silicon substrate and the second made with printed circuit board technology on an alumina substrate. The input capacitances and the admittances between the different trap's electrodes play a critical role in the electronic detection of the trapped particles. The measured input capacitances of the photolithographic chip amount to 65-76 pF, while the values for the printed circuit board chips are in the range of 3-5 pF. The latter are small enough for detecting non-destructively a single trapped electron or ion with a specifically tuned LC resonator. We have also measured a mutual capacitance of ∼85 fF between two of the trap's electrodes in the printed circuit board chip. This enables the detection of single, or very few, trapped particles in a broader range of charge-to-mass ratios with a simple resistor on the chip. We provide analytic calculations of the capacitances and discuss their origin and possible further reduction.
Collapse
Affiliation(s)
- A J Uribe
- Department of Physics and Astronomy, University of Sussex, Falmer BN1 9QH, United Kingdom
| | - A Cridland Mathad
- Department of Physics and Astronomy, University of Sussex, Falmer BN1 9QH, United Kingdom
| | - J H Lacy
- Department of Physics and Astronomy, University of Sussex, Falmer BN1 9QH, United Kingdom
| | - J Pinder
- Department of Physics and Astronomy, University of Sussex, Falmer BN1 9QH, United Kingdom
| | - R Willetts
- Department of Physics and Astronomy, University of Sussex, Falmer BN1 9QH, United Kingdom
| | - J Verdú
- Department of Physics and Astronomy, University of Sussex, Falmer BN1 9QH, United Kingdom
| |
Collapse
|
6
|
Hofierka J, Cunningham B, Rawlins CM, Patterson CH, Green DG. Many-body theory of positron binding to polyatomic molecules. Nature 2022; 606:688-693. [PMID: 35732760 PMCID: PMC9217750 DOI: 10.1038/s41586-022-04703-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 03/30/2022] [Indexed: 02/01/2023]
Abstract
Positron binding to molecules is key to extremely enhanced positron annihilation and positron-based molecular spectroscopy1. Although positron binding energies have been measured for about 90 polyatomic molecules1-6, an accurate ab initio theoretical description of positron-molecule binding has remained elusive. Of the molecules studied experimentally, ab initio calculations exist for only six; these calculations agree with experiments on polar molecules to at best 25 per cent accuracy and fail to predict binding in nonpolar molecules. The theoretical challenge stems from the need to accurately describe the strong many-body correlations including polarization of the electron cloud, screening of the electron-positron Coulomb interaction and the unique process of virtual-positronium formation (in which a molecular electron temporarily tunnels to the positron)1. Here we develop a many-body theory of positron-molecule interactions that achieves excellent agreement with experiment (to within 1 per cent in cases) and predicts binding in formamide and nucleobases. Our framework quantitatively captures the role of many-body correlations and shows their crucial effect on enhancing binding in polar molecules, enabling binding in nonpolar molecules, and increasing annihilation rates by 2 to 3 orders of magnitude. Our many-body approach can be extended to positron scattering and annihilation γ-ray spectra in molecules and condensed matter, to provide the fundamental insight and predictive capability required to improve materials science diagnostics7,8, develop antimatter-based technologies (including positron traps, beams and positron emission tomography)8-10, and understand positrons in the Galaxy11.
Collapse
Affiliation(s)
- Jaroslav Hofierka
- School of Mathematics and Physics, Queen's University Belfast, Belfast, UK
| | - Brian Cunningham
- School of Mathematics and Physics, Queen's University Belfast, Belfast, UK
| | - Charlie M Rawlins
- School of Mathematics and Physics, Queen's University Belfast, Belfast, UK
| | | | - Dermot G Green
- School of Mathematics and Physics, Queen's University Belfast, Belfast, UK.
| |
Collapse
|
7
|
Nandi J, Sikdar AK, Das P, Ray A. Design of a helical resonator with improved figure of merit. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:014706. [PMID: 35104962 DOI: 10.1063/5.0065422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
A helical resonator serves as a key element for the detection of the trapped charged particles in a Penning trap. In order to compare the performance of the helical resonators, the concept of figure of merit (FOM) was introduced by Ulmer et al. [Nucl. Instrum. Methods Phys. Res., Sect. A 705, 55-60 (2013)]. In this work, we optimized the geometrical parameters of a resonator by numerical simulations keeping its outer dimensions and the diameter of the copper wire fixed and obtained the best possible value of FOM under these constraints. The corresponding 95 MHz helical resonator has been designed and fabricated, and its measured value of FOM is in good agreement with the simulated values. An empirical relationship between the total length of the wire to make the helical coil and the resonance frequency has been obtained. The simulations show that the FOM increases considerably with the increase in the conductivity of the building material, and this would be useful in detecting the feeble trap signal in cryogenic environment.
Collapse
Affiliation(s)
- J Nandi
- Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064, India
| | - A K Sikdar
- Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064, India
| | - P Das
- Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064, India
| | - A Ray
- Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064, India
| |
Collapse
|
8
|
Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Christensen A, Collister R, Mathad AC, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Grandemange P, Granum P, Hangst JS, Hardy WN, Hayden ME, Hodgkinson D, Hunter E, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Knapp P, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Mullan PS, Munich JJ, Olchanski K, Olin A, Peszka J, Powell A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Starko DM, So C, Stutter G, Tharp TD, Thibeault A, Thompson RI, van der Werf DP, Wurtele JS. Laser cooling of antihydrogen atoms. Nature 2021; 592:35-42. [PMID: 33790445 PMCID: PMC8012212 DOI: 10.1038/s41586-021-03289-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 01/26/2021] [Indexed: 11/08/2022]
Abstract
The photon-the quantum excitation of the electromagnetic field-is massless but carries momentum. A photon can therefore exert a force on an object upon collision1. Slowing the translational motion of atoms and ions by application of such a force2,3, known as laser cooling, was first demonstrated 40 years ago4,5. It revolutionized atomic physics over the following decades6-8, and it is now a workhorse in many fields, including studies on quantum degenerate gases, quantum information, atomic clocks and tests of fundamental physics. However, this technique has not yet been applied to antimatter. Here we demonstrate laser cooling of antihydrogen9, the antimatter atom consisting of an antiproton and a positron. By exciting the 1S-2P transition in antihydrogen with pulsed, narrow-linewidth, Lyman-α laser radiation10,11, we Doppler-cool a sample of magnetically trapped antihydrogen. Although we apply laser cooling in only one dimension, the trap couples the longitudinal and transverse motions of the anti-atoms, leading to cooling in all three dimensions. We observe a reduction in the median transverse energy by more than an order of magnitude-with a substantial fraction of the anti-atoms attaining submicroelectronvolt transverse kinetic energies. We also report the observation of the laser-driven 1S-2S transition in samples of laser-cooled antihydrogen atoms. The observed spectral line is approximately four times narrower than that obtained without laser cooling. The demonstration of laser cooling and its immediate application has far-reaching implications for antimatter studies. A more localized, denser and colder sample of antihydrogen will drastically improve spectroscopic11-13 and gravitational14 studies of antihydrogen in ongoing experiments. Furthermore, the demonstrated ability to manipulate the motion of antimatter atoms by laser light will potentially provide ground-breaking opportunities for future experiments, such as anti-atomic fountains, anti-atom interferometry and the creation of antimatter molecules.
Collapse
Affiliation(s)
- C J Baker
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - A Capra
- TRIUMF, Vancouver, British Columbia, Canada
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - A Christensen
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | | | - A Cridland Mathad
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - T Friesen
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | | | - D R Gill
- TRIUMF, Vancouver, British Columbia, Canada
| | - P Grandemange
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - P Granum
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - D Hodgkinson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - E Hunter
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - J M Jones
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S A Jones
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - S Jonsell
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - A Khramov
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Physics, British Columbia Institute of Technology, Burnaby, British Columbia, Canada
| | - P Knapp
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | | | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - J T K McKenna
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - J M Michan
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - T Momose
- TRIUMF, Vancouver, British Columbia, Canada.
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada.
| | - P S Mullan
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | | | - A Olin
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada
| | - J Peszka
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - A Powell
- Department of Physics, College of Science, Swansea University, Swansea, UK
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool, UK
| | - C Ø Rasmussen
- Experimental Physics Department, CERN, Geneva, Switzerland
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Sameed
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - E Sarid
- Soreq NRC, Yavne, Israel
- Department of Physics, Ben Gurion University, Beer Sheva, Israel
| | - D M Silveira
- TRIUMF, Vancouver, British Columbia, Canada
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - D M Starko
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - C So
- TRIUMF, Vancouver, British Columbia, Canada
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - T D Tharp
- Physics Department, Marquette University, Milwaukee, WI, USA
| | - A Thibeault
- TRIUMF, Vancouver, British Columbia, Canada
- Faculté de Génie, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - R I Thompson
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| |
Collapse
|
9
|
Hori M. Antimatter cooled by laser light. Nature 2021. [DOI: 10.1038/d41586-021-00786-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
10
|
Analytical Results for the Three-Body Radiative Attachment Rate Coefficient, with Application to the Positive Antihydrogen Ion H+. ATOMS 2020. [DOI: 10.3390/atoms8020013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To overcome the numerical difficulties inherent in the Maxwell–Boltzmann integral of the velocity-weighted cross section that gives the radiative attachment rate coefficient α R A for producing the negative hydrogen ion H − or its antimatter equivalent, the positive antihydrogen ion H ¯ + , we found the analytic form for this integral. This procedure is useful for temperatures below 700 K, the region for which the production of H ¯ + has potential use as an intermediate stage in the cooling of antihydrogen to ultra-cold (sub-mK) temperatures for spectroscopic studies and probing the gravitational interaction of the anti-atom. Our results, utilizing a 50-term explicitly correlated exponential wave function, confirm our prior numerical results.
Collapse
|
11
|
Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Granum P, Hangst JS, Hardy WN, Hayden ME, Hunter ED, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Knapp P, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, So C, Starko DM, Stutter G, Tharp TD, Thompson RI, van der Werf DP, Wurtele JS. Investigation of the fine structure of antihydrogen. Nature 2020; 578:375-380. [PMID: 32076225 PMCID: PMC7162817 DOI: 10.1038/s41586-020-2006-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 12/20/2019] [Indexed: 10/29/2022]
Abstract
At the historic Shelter Island Conference on the Foundations of Quantum Mechanics in 1947, Willis Lamb reported an unexpected feature in the fine structure of atomic hydrogen: a separation of the 2S1/2 and 2P1/2 states1. The observation of this separation, now known as the Lamb shift, marked an important event in the evolution of modern physics, inspiring others to develop the theory of quantum electrodynamics2-5. Quantum electrodynamics also describes antimatter, but it has only recently become possible to synthesize and trap atomic antimatter to probe its structure. Mirroring the historical development of quantum atomic physics in the twentieth century, modern measurements on anti-atoms represent a unique approach for testing quantum electrodynamics and the foundational symmetries of the standard model. Here we report measurements of the fine structure in the n = 2 states of antihydrogen, the antimatter counterpart of the hydrogen atom. Using optical excitation of the 1S-2P Lyman-α transitions in antihydrogen6, we determine their frequencies in a magnetic field of 1 tesla to a precision of 16 parts per billion. Assuming the standard Zeeman and hyperfine interactions, we infer the zero-field fine-structure splitting (2P1/2-2P3/2) in antihydrogen. The resulting value is consistent with the predictions of quantum electrodynamics to a precision of 2 per cent. Using our previously measured value of the 1S-2S transition frequency6,7, we find that the classic Lamb shift in antihydrogen (2S1/2-2P1/2 splitting at zero field) is consistent with theory at a level of 11 per cent. Our observations represent an important step towards precision measurements of the fine structure and the Lamb shift in the antihydrogen spectrum as tests of the charge-parity-time symmetry8 and towards the determination of other fundamental quantities, such as the antiproton charge radius9,10, in this antimatter system.
Collapse
|
12
|
YAMAZAKI Y. Cold and stable antimatter for fundamental physics. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2020; 96:471-501. [PMID: 33390386 PMCID: PMC7859084 DOI: 10.2183/pjab.96.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 10/07/2020] [Indexed: 06/12/2023]
Abstract
The field of cold antimatter physics has rapidly developed in the last 20 years, overlapping with the period of the Antiproton Decelerator (AD) at CERN. The central subjects are CPT symmetry tests and Weak Equivalence Principle (WEP) tests. Various groundbreaking techniques have been developed and are still in progress such as to cool antiprotons and positrons down to extremely low temperature, to manipulate antihydrogen atoms, to construct extremely high-precision Penning traps, etc. The precisions of the antiproton and proton magnetic moments have improved by six orders of magnitude, and also laser spectroscopy of antihydrogen has been realized and reached a relative precision of 2 × 10-12 during the AD time. Antiprotonic helium laser spectroscopy, which started during the Low Energy Antiproton Ring (LEAR) time, has reached a relative precision of 8 × 10-10. Three collaborations joined the WEP tests inventing various unique approaches. An additional new post-decelerator, Extra Low ENergy Antiproton ring (ELENA), has been constructed and will be ready in 2021, which will provide 10-100 times more cold antiprotons to each experiment. A new era of the cold antimatter physics will emerge soon including the transport of antiprotons to other facilities.
Collapse
|
13
|
Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayden ME, Hunter ED, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Knapp P, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Starko DM, Stutter G, So C, Tharp TD, Thompson RI, van der Werf DP, Wurtele JS. Observation of the 1S-2P Lyman-α transition in antihydrogen. Nature 2018; 561:211-215. [PMID: 30135588 PMCID: PMC6786973 DOI: 10.1038/s41586-018-0435-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 07/05/2018] [Indexed: 11/09/2022]
Abstract
In 1906, Theodore Lyman discovered his eponymous series of transitions in the extreme-ultraviolet region of the atomic hydrogen spectrum1,2. The patterns in the hydrogen spectrum helped to establish the emerging theory of quantum mechanics, which we now know governs the world at the atomic scale. Since then, studies involving the Lyman-α line-the 1S-2P transition at a wavelength of 121.6 nanometres-have played an important part in physics and astronomy, as one of the most fundamental atomic transitions in the Universe. For example, this transition has long been used by astronomers studying the intergalactic medium and testing cosmological models via the so-called 'Lyman-α forest'3 of absorption lines at different redshifts. Here we report the observation of the Lyman-α transition in the antihydrogen atom, the antimatter counterpart of hydrogen. Using narrow-line-width, nanosecond-pulsed laser radiation, the 1S-2P transition was excited in magnetically trapped antihydrogen. The transition frequency at a field of 1.033 tesla was determined to be 2,466,051.7 ± 0.12 gigahertz (1σ uncertainty) and agrees with the prediction for hydrogen to a precision of 5 × 10-8. Comparisons of the properties of antihydrogen with those of its well-studied matter equivalent allow precision tests of fundamental symmetries between matter and antimatter. Alongside the ground-state hyperfine4,5 and 1S-2S transitions6,7 recently observed in antihydrogen, the Lyman-α transition will permit laser cooling of antihydrogen8,9, thus providing a cold and dense sample of anti-atoms for precision spectroscopy and gravity measurements10. In addition to the observation of this fundamental transition, this work represents both a decisive technological step towards laser cooling of antihydrogen, and the extension of antimatter spectroscopy to quantum states possessing orbital angular momentum.
Collapse
Affiliation(s)
- M Ahmadi
- Department of Physics, University of Liverpool, Liverpool, UK
| | - B X R Alves
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C J Baker
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - A Capra
- TRIUMF, Vancouver, British Columbia, Canada
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S Cohen
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | | | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - T Friesen
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | | | - D R Gill
- TRIUMF, Vancouver, British Columbia, Canada
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - E D Hunter
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - J M Jones
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S A Jones
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S Jonsell
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - A Khramov
- TRIUMF, Vancouver, British Columbia, Canada
| | - P Knapp
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | | | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | | | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - J M Michan
- TRIUMF, Vancouver, British Columbia, Canada
- École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), Lausanne, Switzerland
| | - T Momose
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada.
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada.
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | | | - A Olin
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool, UK
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Sameed
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | | | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - D M Starko
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C So
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - T D Tharp
- Physics Department, Marquette University, Milwaukee, WI, USA
| | - R I Thompson
- TRIUMF, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea, UK
- IRFU, CEA/Saclay, Gif-sur-Yvette Cedex, France
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| |
Collapse
|
14
|
|
15
|
Charry J, Varella MTDN, Reyes A. Binding Matter with Antimatter: The Covalent Positron Bond. Angew Chem Int Ed Engl 2018; 57:8859-8864. [DOI: 10.1002/anie.201800914] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Jorge Charry
- Universidad Nacional de Colombia Chemistry; Av. cra 30 #45-03 Bogota, 00000 Colombia
| | - Márcio T. do N. Varella
- Instituto de Física; Universidade de São Paulo; Rua do Matão 1731 05508-090 São Paulo, SP Brazil
| | - Andrés Reyes
- Universidad Nacional de Colombia Chemistry; Av. cra 30 #45-03 Bogota, 00000 Colombia
| |
Collapse
|
16
|
|
17
|
Plašil R, Dohnal P, Kálosi Á, Roučka Š, Shapko D, Rednyk S, Johnsen R, Glosík J. Stationary afterglow apparatus with CRDS for study of processes in plasmas from 300 K down to 30 K. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:063116. [PMID: 29960549 DOI: 10.1063/1.5036834] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A cryogenic stationary afterglow apparatus equipped with a near-infrared cavity-ring-down-spectrometer (Cryo-SA-CRDS) for studies of electron-ion recombination processes in the plasma at temperatures 30-300 K has been designed, constructed, tested, and put into operation. The plasma is generated in a sapphire discharge tube that is contained in a microwave cavity. The cavity and the tube are attached to the second stage of the cold head of the cryocooler system, and they are inserted to an UHV chamber with mirrors for CRDS and vacuum windows on both ends of the tube. The temperature of the discharge tube can be made as low as 25 K. In initial test measurements, the discharge was ignited in He/Ar/H2 or He/H2 gas mixtures and the density of H3+ ions and their kinetic and rotational temperatures were measured during the discharge and afterglow. From the measured decrease in the ion density, during the afterglow, effective recombination rate coefficients were determined. Plasma relaxation was studied in He/Ar gas mixtures by monitoring the presence of highly excited argon atoms. The spectroscopic measurements demonstrated that the kinetic temperature of the ions is equal to the gas temperature and that it can be varied from 300 K down to 30 K.
Collapse
Affiliation(s)
- R Plašil
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - P Dohnal
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - Á Kálosi
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - Š Roučka
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - D Shapko
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - S Rednyk
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - R Johnsen
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - J Glosík
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| |
Collapse
|
18
|
Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Johnson MA, Jones JM, Jones SA, Jonsell S, Khramov A, Knapp P, Kurchaninov L, Madsen N, Maxwell D, McKenna JTK, Menary S, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stutter G, So C, Tharp TD, Thompson RI, van der Werf DP, Wurtele JS. Characterization of the 1S-2S transition in antihydrogen. Nature 2018; 557:71-75. [PMID: 29618820 PMCID: PMC6784861 DOI: 10.1038/s41586-018-0017-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/06/2018] [Indexed: 11/09/2022]
Abstract
In 1928, Dirac published an equation 1 that combined quantum mechanics and special relativity. Negative-energy solutions to this equation, rather than being unphysical as initially thought, represented a class of hitherto unobserved and unimagined particles-antimatter. The existence of particles of antimatter was confirmed with the discovery of the positron 2 (or anti-electron) by Anderson in 1932, but it is still unknown why matter, rather than antimatter, survived after the Big Bang. As a result, experimental studies of antimatter3-7, including tests of fundamental symmetries such as charge-parity and charge-parity-time, and searches for evidence of primordial antimatter, such as antihelium nuclei, have high priority in contemporary physics research. The fundamental role of the hydrogen atom in the evolution of the Universe and in the historical development of our understanding of quantum physics makes its antimatter counterpart-the antihydrogen atom-of particular interest. Current standard-model physics requires that hydrogen and antihydrogen have the same energy levels and spectral lines. The laser-driven 1S-2S transition was recently observed 8 in antihydrogen. Here we characterize one of the hyperfine components of this transition using magnetically trapped atoms of antihydrogen and compare it to model calculations for hydrogen in our apparatus. We find that the shape of the spectral line agrees very well with that expected for hydrogen and that the resonance frequency agrees with that in hydrogen to about 5 kilohertz out of 2.5 × 1015 hertz. This is consistent with charge-parity-time invariance at a relative precision of 2 × 10-12-two orders of magnitude more precise than the previous determination 8 -corresponding to an absolute energy sensitivity of 2 × 10-20 GeV.
Collapse
Affiliation(s)
- M Ahmadi
- Department of Physics, University of Liverpool, Liverpool, UK
| | - B X R Alves
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C J Baker
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - A Capra
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S Cohen
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - R Collister
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - T Friesen
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - D R Gill
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, UK
- Cockcroft Institute, Sci-Tech Daresbury, Warrington, UK
| | - J M Jones
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S A Jones
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - S Jonsell
- Department of Physics, Stockholm University, Stockholm, Sweden
| | - A Khramov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - P Knapp
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea, UK
| | - J T K McKenna
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada
| | - T Momose
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool, UK
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - M Sameed
- Department of Physics, College of Science, Swansea University, Swansea, UK
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | | | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - C So
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - T D Tharp
- Physics Department, Marquette University, Milwaukee, WI, USA
| | - R I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea, UK
- IRFU, CEA/Saclay, Gif-sur-Yvette Cedex, France
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| |
Collapse
|
19
|
Cerchiari G, Kellerbauer A, Safronova MS, Safronova UI, Yzombard P. Ultracold Anions for High-Precision Antihydrogen Experiments. PHYSICAL REVIEW LETTERS 2018; 120:133205. [PMID: 29694180 DOI: 10.1103/physrevlett.120.133205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Indexed: 06/08/2023]
Abstract
Experiments with antihydrogen (H[over ¯]) for a study of matter-antimatter symmetry and antimatter gravity require ultracold H[over ¯] to reach ultimate precision. A promising path towards antiatoms much colder than a few kelvin involves the precooling of antiprotons by laser-cooled anions. Because of the weak binding of the valence electron in anions-dominated by polarization and correlation effects-only few candidate systems with suitable transitions exist. We report on a combination of experimental and theoretical studies to fully determine the relevant binding energies, transition rates, and branching ratios of the most promising candidate La^{-}. Using combined transverse and collinear laser spectroscopy, we determined the resonant frequency of the laser cooling transition to be ν=96.592 713(91) THz and its transition rate to be A=4.90(50)×10^{4} s^{-1}. Using a novel high-precision theoretical treatment of La^{-} we calculated yet unmeasured energy levels, transition rates, branching ratios, and lifetimes to complement experimental information on the laser cooling cycle of La^{-}. The new data establish the suitability of La^{-} for laser cooling and show that the cooling transition is significantly stronger than suggested by a previous theoretical study.
Collapse
Affiliation(s)
- G Cerchiari
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - A Kellerbauer
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - M S Safronova
- Department of Physics and Astronomy, University of Delaware, 217 Sharp Lab, Newark, Delaware 19716, USA
- Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, Maryland 20742, USA
| | - U I Safronova
- Physics Department, University of Nevada, Reno, Nevada 89557, USA
| | - P Yzombard
- Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany
| |
Collapse
|
20
|
Eriksson S. Precision measurements on trapped antihydrogen in the ALPHA experiment. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:20170268. [PMID: 29459409 PMCID: PMC5829172 DOI: 10.1098/rsta.2017.0268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/01/2017] [Indexed: 06/08/2023]
Abstract
Both the 1S-2S transition and the ground state hyperfine spectrum have been observed in trapped antihydrogen. The former constitutes the first observation of resonant interaction of light with an anti-atom, and the latter is the first detailed measurement of a spectral feature in antihydrogen. Owing to the narrow intrinsic linewidth of the 1S-2S transition and use of two-photon laser excitation, the transition energy can be precisely determined in both hydrogen and antihydrogen, allowing a direct comparison as a test of fundamental symmetry. The result is consistent with CPT invariance at a relative precision of around 2×10-10 This constitutes the most precise measurement of a property of antihydrogen. The hyperfine spectrum of antihydrogen is determined to a relative uncertainty of 4×10-4 The excited state and the hyperfine spectroscopy techniques currently both show sensitivity at the few 100 kHz level on the absolute scale. Here, the most recent work of the ALPHA collaboration on precision spectroscopy of antihydrogen is presented together with an outlook on improving the precision of measurements involving lasers and microwave radiation. Prospects of measuring the Lamb shift and determining the antiproton charge radius in trapped antihydrogen in the ALPHA apparatus are presented. Future perspectives of precision measurements of trapped antihydrogen in the ALPHA apparatus when the ELENA facility becomes available to experiments at CERN are discussed.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'.
Collapse
Affiliation(s)
- S Eriksson
- Department of Physics, College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, UK
| |
Collapse
|
21
|
Bertsche WA. Prospects for comparison of matter and antimatter gravitation with ALPHA-g. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:20170265. [PMID: 29459415 PMCID: PMC5829170 DOI: 10.1098/rsta.2017.0265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 11/24/2017] [Indexed: 06/08/2023]
Abstract
The ALPHA experiment has recently entered an expansion phase of its experimental programme, driven in part by the expected benefits of conducting experiments in the framework of the new AD + ELENA antiproton facility at CERN. With antihydrogen trapping now a routine operation in the ALPHA experiment, the collaboration is leading progress towards precision atomic measurements on trapped antihydrogen atoms, with the first excitation of the 1S-2S transition and the first measurement of the antihydrogen hyperfine spectrum (Ahmadi et al. 2017 Nature541, 506-510 (doi:10.1038/nature21040); Nature548, 66-69 (doi:10.1038/nature23446)). We are building on these successes to extend our physics programme to include a measurement of antimatter gravitation. We plan to expand a proof-of-principle method (Amole et al. 2013 Nat. Commun.4, 1785 (doi:10.1038/ncomms2787)), first demonstrated in the original ALPHA apparatus, and perform a precise measurement of antimatter gravitational acceleration with the aim of achieving a test of the weak equivalence principle at the 1% level. The design of this apparatus has drawn from a growing body of experience on the simulation and verification of antihydrogen orbits confined within magnetic-minimum atom traps. The new experiment, ALPHA-g, will be an additional atom-trapping apparatus located at the ALPHA experiment with the intention of measuring antihydrogen gravitation.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'.
Collapse
Affiliation(s)
- W A Bertsche
- University of Manchester, School of Physics and Astronomy, Oxford Road, Manchester M13 9PL, UK
- The Cockcroft Institute, Keckwick Lane, Daresbury, Warrington WA4 4AD, UK
| |
Collapse
|
22
|
Malbrunot C, Amsler C, Arguedas Cuendis S, Breuker H, Dupre P, Fleck M, Higaki H, Kanai Y, Kolbinger B, Kuroda N, Leali M, Mäckel V, Mascagna V, Massiczek O, Matsuda Y, Nagata Y, Simon MC, Spitzer H, Tajima M, Ulmer S, Venturelli L, Widmann E, Wiesinger M, Yamazaki Y, Zmeskal J. The ASACUSA antihydrogen and hydrogen program: results and prospects. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:rsta.2017.0273. [PMID: 29459412 PMCID: PMC5829175 DOI: 10.1098/rsta.2017.0273] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 12/18/2017] [Indexed: 06/08/2023]
Abstract
The goal of the ASACUSA-CUSP collaboration at the Antiproton Decelerator of CERN is to measure the ground-state hyperfine splitting of antihydrogen using an atomic spectroscopy beamline. A milestone was achieved in 2012 through the detection of 80 antihydrogen atoms 2.7 m away from their production region. This was the first observation of 'cold' antihydrogen in a magnetic field free region. In parallel to the progress on the antihydrogen production, the spectroscopy beamline was tested with a source of hydrogen. This led to a measurement at a relative precision of 2.7×10-9 which constitutes the most precise measurement of the hydrogen hyperfine splitting in a beam. Further measurements with an upgraded hydrogen apparatus are motivated by CPT and Lorentz violation tests in the framework of the Standard Model Extension. Unlike for hydrogen, the antihydrogen experiment is complicated by the difficulty of synthesizing enough cold antiatoms in the ground state. The first antihydrogen quantum states scan at the entrance of the spectroscopy apparatus was realized in 2016 and is presented here. The prospects for a ppm measurement are also discussed.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'.
Collapse
Affiliation(s)
- C Malbrunot
- Experimental Physics Department, CERN, Genève 23, 1211, Switzerland
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - C Amsler
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - S Arguedas Cuendis
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - H Breuker
- Ulmer Fundamental Symmetries Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - P Dupre
- Ulmer Fundamental Symmetries Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - M Fleck
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - H Higaki
- Graduate School of Advanced Sciences of Matter, Hiroshima University, Hiroshima 739-8530, Japan
| | - Y Kanai
- Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - B Kolbinger
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - N Kuroda
- Institute of Physics, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - M Leali
- Dipartimento di Ingegneria dell'Informazione, Università di Brescia, Brescia 25133, Italy
- Istituto Nazionale di Fisica Nucleare, Sez. di Pavia, 27100 Pavia, Italy
| | - V Mäckel
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - V Mascagna
- Dipartimento di Ingegneria dell'Informazione, Università di Brescia, Brescia 25133, Italy
- Istituto Nazionale di Fisica Nucleare, Sez. di Pavia, 27100 Pavia, Italy
| | - O Massiczek
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - Y Matsuda
- Institute of Physics, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - Y Nagata
- Department of Physics, Tokyo University of Science, Shinjuku, Tokyo 162-8601, Japan
| | - M C Simon
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - H Spitzer
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - M Tajima
- Institute of Physics, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
| | - S Ulmer
- Ulmer Fundamental Symmetries Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - L Venturelli
- Dipartimento di Ingegneria dell'Informazione, Università di Brescia, Brescia 25133, Italy
- Istituto Nazionale di Fisica Nucleare, Sez. di Pavia, 27100 Pavia, Italy
| | - E Widmann
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - M Wiesinger
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| | - Y Yamazaki
- Ulmer Fundamental Symmetries Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - J Zmeskal
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Wien, Austria
| |
Collapse
|
23
|
Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Momose T, Munich JJ, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, So C, Stutter G, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Enhanced Control and Reproducibility of Non-Neutral Plasmas. PHYSICAL REVIEW LETTERS 2018; 120:025001. [PMID: 29376718 DOI: 10.1103/physrevlett.120.025001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Indexed: 06/07/2023]
Abstract
The simultaneous control of the density and particle number of non-neutral plasmas confined in Penning-Malmberg traps is demonstrated. Control is achieved by setting the plasma's density by applying a rotating electric field while simultaneously fixing its axial potential via evaporative cooling. This novel method is particularly useful for stabilizing positron plasmas, as the procedures used to collect positrons from radioactive sources typically yield plasmas with variable densities and particle numbers; it also simplifies optimization studies that require plasma parameter scans. The reproducibility achieved by applying this technique to the positron and electron plasmas used by the ALPHA antihydrogen experiment at CERN, combined with other developments, contributed to a 10-fold increase in the antiatom trapping rate.
Collapse
Affiliation(s)
- M Ahmadi
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - B X R Alves
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - C J Baker
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
- Cockcroft Institute, Sci-Tech Daresbury, Warrington WA4 4AD, United Kingdom
| | - A Capra
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - C L Cesar
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - S Cohen
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - R Collister
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - N Evetts
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - T Friesen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - D R Gill
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - W N Hardy
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - S A Jones
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - S Jonsell
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - M Mathers
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
| | - J T K McKenna
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - T Momose
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - R L Sacramento
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - M Sameed
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
| | - E Sarid
- Soreq NRC, Yavne 81800, Israel
| | - D M Silveira
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - C So
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - T D Tharp
- Physics Department, Marquette University, P.O. Box 1881,Milwaukee, Wisconsin 53201-1881, USA
| | - J E Thompson
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - R I Thompson
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, United Kingdom
- IRFU, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| |
Collapse
|
24
|
Kadyrov AS, Bray I, Charlton M, Fabrikant II. Quantum suppression of antihydrogen formation in positronium-antiproton scattering. Nat Commun 2017; 8:1544. [PMID: 29146898 PMCID: PMC5691179 DOI: 10.1038/s41467-017-01721-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 10/10/2017] [Indexed: 11/08/2022] Open
Abstract
The interaction of antiprotons with low-energy positronium atoms is a fundamental three-body problem whose significance is its utility for formation of antihydrogen. Particular importance resides in understanding processes involving excited positronium states. Until recently such studies were performed using classical techniques. However, they become inapplicable in the low-energy domain. Here we report the results of comprehensive quantum calculations, which include initial excited positronium states with principal quantum numbers up to n i = 5. Contrary to expectation from earlier work, there are only muted increases in the cross-sections for antihydrogen formation for n i > 3. We interpret this in terms of quantum suppression of the reaction at higher angular momenta. Furthermore, the cross-sections for elastic scattering are around two orders of magnitude higher, which we attribute to the degeneracy of the positronium states. We outline some experimental consequences of our results.
Collapse
Affiliation(s)
- A S Kadyrov
- Curtin Institute for Computation and Department of Physics, Astronomy and Medical Radiation Science, Curtin University, GPO Box U1987, Perth, WA, 6845, Australia.
| | - I Bray
- Curtin Institute for Computation and Department of Physics, Astronomy and Medical Radiation Science, Curtin University, GPO Box U1987, Perth, WA, 6845, Australia
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - I I Fabrikant
- Department of Physics and Astronomy, University of Nebraska, Lincoln, NE, 68588-0299, USA
| |
Collapse
|
25
|
Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Butler E, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Ishida A, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stracka S, Stutter G, So C, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Observation of the hyperfine spectrum of antihydrogen. Nature 2017; 548:66-69. [PMID: 28770838 DOI: 10.1038/nature23446] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 06/30/2017] [Indexed: 11/09/2022]
Abstract
The observation of hyperfine structure in atomic hydrogen by Rabi and co-workers and the measurement of the zero-field ground-state splitting at the level of seven parts in 1013 are important achievements of mid-twentieth-century physics. The work that led to these achievements also provided the first evidence for the anomalous magnetic moment of the electron, inspired Schwinger's relativistic theory of quantum electrodynamics and gave rise to the hydrogen maser, which is a critical component of modern navigation, geo-positioning and very-long-baseline interferometry systems. Research at the Antiproton Decelerator at CERN by the ALPHA collaboration extends these enquiries into the antimatter sector. Recently, tools have been developed that enable studies of the hyperfine structure of antihydrogen-the antimatter counterpart of hydrogen. The goal of such studies is to search for any differences that might exist between this archetypal pair of atoms, and thereby to test the fundamental principles on which quantum field theory is constructed. Magnetic trapping of antihydrogen atoms provides a means of studying them by combining electromagnetic interaction with detection techniques that are unique to antimatter. Here we report the results of a microwave spectroscopy experiment in which we probe the response of antihydrogen over a controlled range of frequencies. The data reveal clear and distinct signatures of two allowed transitions, from which we obtain a direct, magnetic-field-independent measurement of the hyperfine splitting. From a set of trials involving 194 detected atoms, we determine a splitting of 1,420.4 ± 0.5 megahertz, consistent with expectations for atomic hydrogen at the level of four parts in 104. This observation of the detailed behaviour of a quantum transition in an atom of antihydrogen exemplifies tests of fundamental symmetries such as charge-parity-time in antimatter, and the techniques developed here will enable more-precise such tests.
Collapse
Affiliation(s)
- M Ahmadi
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - B X R Alves
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - C J Baker
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester M12 9PL, UK.,Cockcroft Institute, Sci-Tech Daresbury, Warrington WA4 4AD, UK
| | - E Butler
- Physics Department, CERN, CH-1211 Geneve 23, Switzerland
| | - A Capra
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - S Cohen
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - R Collister
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - T Friesen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - D R Gill
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - A Gutierrez
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.,Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, UK
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - A Ishida
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester M12 9PL, UK.,Cockcroft Institute, Sci-Tech Daresbury, Warrington WA4 4AD, UK
| | - S A Jones
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - S Jonsell
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - M Mathers
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - J T K McKenna
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - J M Michan
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.,École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), Lausanne CH-1015, Switzerland
| | - T Momose
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - P Nolan
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.,Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - M Sameed
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - E Sarid
- Soreq NRC, Yavne 81800, Israel
| | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - S Stracka
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.,Universita di Pisa and Sezione INFN di Pisa, Largo Pontecorvo 3, 56127 Pisa, Italy
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - C So
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - T D Tharp
- Physics Department, Marquette University, PO Box 1881, Milwaukee, Wisconsin 53201-1881, USA
| | - J E Thompson
- Department of Physics and Astronomy, York University, Toronto, Ontario M3J 1P3, Canada
| | - R I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK.,IRFU, CEA/Saclay, F-91191, Gif-sur-Yvette Cedex, France
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| |
Collapse
|
26
|
Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Butler E, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Ishida A, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stracka S, Stutter G, So C, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Antihydrogen accumulation for fundamental symmetry tests. Nat Commun 2017; 8:681. [PMID: 28947794 PMCID: PMC5613003 DOI: 10.1038/s41467-017-00760-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 07/20/2017] [Indexed: 11/18/2022] Open
Abstract
Antihydrogen, a positron bound to an antiproton, is the simplest anti-atom. Its structure and properties are expected to mirror those of the hydrogen atom. Prospects for precision comparisons of the two, as tests of fundamental symmetries, are driving a vibrant programme of research. In this regard, a limiting factor in most experiments is the availability of large numbers of cold ground state antihydrogen atoms. Here, we describe how an improved synthesis process results in a maximum rate of 10.5 ± 0.6 atoms trapped and detected per cycle, corresponding to more than an order of magnitude improvement over previous work. Additionally, we demonstrate how detailed control of electron, positron and antiproton plasmas enables repeated formation and trapping of antihydrogen atoms, with the simultaneous retention of atoms produced in previous cycles. We report a record of 54 detected annihilation events from a single release of the trapped anti-atoms accumulated from five consecutive cycles. Antihydrogen studies are important in testing the fundamental principles of physics but producing antihydrogen in large amounts is challenging. Here the authors demonstrate an efficient and high-precision method for trapping and stacking antihydrogen by using controlled plasma.
Collapse
Affiliation(s)
- M Ahmadi
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, UK
| | - B X R Alves
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - C J Baker
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - W Bertsche
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK.,Cockcroft Institute, Sci-Tech Daresbury, Warrington, WA4 4AD, UK
| | - E Butler
- Physics Department, CERN, CH-1211, Geneve 23, Switzerland
| | - A Capra
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - C Carruth
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720-7300, USA
| | - C L Cesar
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - S Cohen
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - R Collister
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - A Evans
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada, T2N 1N4
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1
| | - J Fajans
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720-7300, USA
| | - T Friesen
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark.
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - D R Gill
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - A Gutierrez
- Department of Medical Physics and Biomedical Engineering, University College London, London, WC1E 6BT, UK
| | - J S Hangst
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - A Ishida
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Tokyo, 113-0033, Japan
| | - M A Johnson
- School of Physics and Astronomy, University of Manchester, Manchester, M12 9PL, UK.,Cockcroft Institute, Sci-Tech Daresbury, Warrington, WA4 4AD, UK
| | - S A Jones
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - S Jonsell
- Department of Physics, Stockholm University, SE-10691, Stockholm, Sweden
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK.
| | - M Mathers
- Department of Physics and Astronomy, York University, Toronto, ON, Canada, M3J 1P3
| | - D Maxwell
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - J T K McKenna
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, ON, Canada, M3J 1P3
| | - J M Michan
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3.,École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015, Lausanne, Switzerland
| | - T Momose
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada, V6T 1Z1
| | - J J Munich
- Department of Physics, Simon Fraser University, Burnaby, BC, Canada, V5A 1S6
| | - P Nolan
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, UK
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, Canada, V6T 2A3.,Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada, V8P 5C2
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, UK
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, 47907, USA
| | - R L Sacramento
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - M Sameed
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - E Sarid
- Soreq NRC, Yavne, 81800, Israel
| | - D M Silveira
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-972, Brazil
| | - S Stracka
- Universita di Pisa and Sezione INFN di Pisa, Largo Pontecorvo 3, 56127, Pisa, Italy
| | - G Stutter
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - C So
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada, T2N 1N4
| | - T D Tharp
- Physics Department, Marquette University, P.O. Box 1881, Milwaukee, WI, 53201-1881, USA
| | - J E Thompson
- Department of Physics and Astronomy, York University, Toronto, ON, Canada, M3J 1P3
| | - R I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada, T2N 1N4
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea, SA2 8PP, UK.,IRFU, CEA/Saclay, F-91191, Gif-sur-Yvette, France
| | - J S Wurtele
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720-7300, USA
| |
Collapse
|
27
|
Diermaier M, Jepsen CB, Kolbinger B, Malbrunot C, Massiczek O, Sauerzopf C, Simon MC, Zmeskal J, Widmann E. In-beam measurement of the hydrogen hyperfine splitting and prospects for antihydrogen spectroscopy. Nat Commun 2017; 8:15749. [PMID: 28604657 PMCID: PMC5472788 DOI: 10.1038/ncomms15749] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 04/24/2017] [Indexed: 11/09/2022] Open
Abstract
Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison with hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment, to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA's antihydrogen experiment. The measured value of νHF=1,420,405,748.4(3.4) (1.6) Hz with a relative precision of 2.7 × 10-9 constitutes the most precise determination of this quantity in a beam and verifies the developed spectroscopy methods for the antihydrogen HFS experiment to the p.p.b. level. Together with the recently presented observation of antihydrogen atoms 2.7 m downstream of the production region, the prerequisites for a measurement with antihydrogen are now available within the ASACUSA collaboration.
Collapse
Affiliation(s)
- M. Diermaier
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, Wien 1090, Austria
| | - C. B. Jepsen
- Experimental Physics Department, CERN, Genève 23, CH-1211, Switzerland
| | - B. Kolbinger
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, Wien 1090, Austria
| | - C. Malbrunot
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, Wien 1090, Austria
- Experimental Physics Department, CERN, Genève 23, CH-1211, Switzerland
| | - O. Massiczek
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, Wien 1090, Austria
| | - C. Sauerzopf
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, Wien 1090, Austria
| | - M. C. Simon
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, Wien 1090, Austria
| | - J. Zmeskal
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, Wien 1090, Austria
| | - E. Widmann
- Stefan-Meyer-Institut für Subatomare Physik, Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, Wien 1090, Austria
| |
Collapse
|
28
|
Physics: Optical transition seen in antihydrogen. Nature 2017; 541:467-468. [PMID: 28128254 DOI: 10.1038/541467a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
29
|
Ahmadi M, Alves BXR, Baker CJ, Bertsche W, Butler E, Capra A, Carruth C, Cesar CL, Charlton M, Cohen S, Collister R, Eriksson S, Evans A, Evetts N, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Ishida A, Johnson MA, Jones SA, Jonsell S, Kurchaninov L, Madsen N, Mathers M, Maxwell D, McKenna JTK, Menary S, Michan JM, Momose T, Munich JJ, Nolan P, Olchanski K, Olin A, Pusa P, Rasmussen CØ, Robicheaux F, Sacramento RL, Sameed M, Sarid E, Silveira DM, Stracka S, Stutter G, So C, Tharp TD, Thompson JE, Thompson RI, van der Werf DP, Wurtele JS. Observation of the 1S–2S transition in trapped antihydrogen. Nature 2016; 541:506-510. [DOI: 10.1038/nature21040] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 12/07/2016] [Indexed: 11/09/2022]
|
30
|
Povilus AP, DeTal ND, Evans LT, Evetts N, Fajans J, Hardy WN, Hunter ED, Martens I, Robicheaux F, Shanman S, So C, Wang X, Wurtele JS. Electron Plasmas Cooled by Cyclotron-Cavity Resonance. PHYSICAL REVIEW LETTERS 2016; 117:175001. [PMID: 27824477 DOI: 10.1103/physrevlett.117.175001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Indexed: 06/06/2023]
Abstract
We observe that high-Q electromagnetic cavity resonances increase the cyclotron cooling rate of pure electron plasmas held in a Penning-Malmberg trap when the electron cyclotron frequency, controlled by tuning the magnetic field, matches the frequency of standing wave modes in the cavity. For certain modes and trapping configurations, this can increase the cooling rate by factors of 10 or more. In this Letter, we investigate the variation of the cooling rate and equilibrium plasma temperatures over a wide range of parameters, including the plasma density, plasma position, electron number, and magnetic field.
Collapse
Affiliation(s)
- A P Povilus
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - N D DeTal
- Department of Physics and Astronomy, Beloit College, Beloit, Wisconsin 53511, USA
| | - L T Evans
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - J Fajans
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - E D Hunter
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - I Martens
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - F Robicheaux
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - S Shanman
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - C So
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - X Wang
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, USA
| | - J S Wurtele
- Department of Physics, University of California, Berkeley, California 94720, USA
| |
Collapse
|
31
|
Affolter M, Anderegg F, Dubin DHE, Driscoll CF. First Test of Long-Range Collisional Drag via Plasma Wave Damping. PHYSICAL REVIEW LETTERS 2016; 117:155001. [PMID: 27768331 DOI: 10.1103/physrevlett.117.155001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Indexed: 06/06/2023]
Abstract
This paper presents the first experimental confirmation of a new theory predicting enhanced drag due to long-range collisions in a magnetized plasma. The experiments measure damping of Langmuir waves in a multispecies pure ion plasma, which is dominated by interspecies collisional drag in certain regimes. The measured damping rates in these regimes exceed classical predictions of collisional drag damping by as much as an order of magnitude, but agree with the new theory.
Collapse
Affiliation(s)
- M Affolter
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
| | - F Anderegg
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
| | - D H E Dubin
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
| | - C F Driscoll
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
| |
Collapse
|
32
|
An improved limit on the charge of antihydrogen from stochastic acceleration. Nature 2016; 529:373-6. [PMID: 26791725 DOI: 10.1038/nature16491] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 11/17/2015] [Indexed: 11/08/2022]
Abstract
Antimatter continues to intrigue physicists because of its apparent absence in the observable Universe. Current theory requires that matter and antimatter appeared in equal quantities after the Big Bang, but the Standard Model of particle physics offers no quantitative explanation for the apparent disappearance of half the Universe. It has recently become possible to study trapped atoms of antihydrogen to search for possible, as yet unobserved, differences in the physical behaviour of matter and antimatter. Here we consider the charge neutrality of the antihydrogen atom. By applying stochastic acceleration to trapped antihydrogen atoms, we determine an experimental bound on the antihydrogen charge, Qe, of |Q| < 0.71 parts per billion (one standard deviation), in which e is the elementary charge. This bound is a factor of 20 less than that determined from the best previous measurement of the antihydrogen charge. The electrical charge of atoms and molecules of normal matter is known to be no greater than about 10(-21)e for a diverse range of species including H2, He and SF6. Charge-parity-time symmetry and quantum anomaly cancellation demand that the charge of antihydrogen be similarly small. Thus, our measurement constitutes an improved limit and a test of fundamental aspects of the Standard Model. If we assume charge superposition and use the best measured value of the antiproton charge, then we can place a new limit on the positron charge anomaly (the relative difference between the positron and elementary charge) of about one part per billion (one standard deviation), a 25-fold reduction compared to the current best measurement.
Collapse
|
33
|
Hogan SD. Rydberg-Stark deceleration of atoms and molecules. EPJ TECHNIQUES AND INSTRUMENTATION 2016; 3:2. [PMID: 32355605 PMCID: PMC7175735 DOI: 10.1140/epjti/s40485-015-0028-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/27/2015] [Indexed: 06/06/2023]
Abstract
The large electric dipole moments associated with highly excited Rydberg states of atoms and molecules make gas-phase samples in these states very well suited to deceleration and trapping using inhomogeneous electric fields. The methods of Rydberg-Stark deceleration with which this can be achieved are reviewed here. Using these techniques, the longitudinal motion of beams of atoms and molecules moving at speeds as high as 2500 m/s have been manipulated, with changes in kinetic energy of up to |Δ E kin|=1.3×10-20 J (|Δ E kin|/e=80 meV or |Δ E kin|/h c=650 cm -1) achieved, while decelerated and trapped samples with number densities of 106- 107 cm -3 and translational temperatures of ∼150 mK have been prepared. Applications of these samples in areas of research at the interface between physics and physical chemistry are discussed.
Collapse
Affiliation(s)
- Stephen D. Hogan
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
| |
Collapse
|
34
|
Evetts N, Dosanjh P, Zvyagintsev V, Hardy WN. Note: A cryogenic, ultra-high-vacuum, microwave filter which passes a narrow beam. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:126101. [PMID: 26724082 DOI: 10.1063/1.4936594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report on a device which filters microwave radiation prone to heating cryogenic experiments while at the same time allowing large apertures which will not disturb a propagating beam. A method for evaporating thin films onto the inner face of a narrow tube is also described.
Collapse
Affiliation(s)
- N Evetts
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - P Dosanjh
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - V Zvyagintsev
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - W N Hardy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| |
Collapse
|
35
|
Sacramento RL, Oliveira AN, Alves BX, Silva BA, Li MS, Wolff W, Cesar CL. Matrix isolation sublimation: An apparatus for producing cryogenic beams of atoms and molecules. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:073109. [PMID: 26233358 DOI: 10.1063/1.4926774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We describe the apparatus to generate cryogenic beams of atoms and molecules based on matrix isolation sublimation. Isolation matrices of Ne and H2 are hosts for atomic and molecular species which are sublimated into vacuum at cryogenic temperatures. The resulting cryogenic beams are used for high-resolution laser spectroscopy. The technique also aims at loading atomic and molecular traps.
Collapse
Affiliation(s)
- R L Sacramento
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| | - A N Oliveira
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| | - B X Alves
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| | - B A Silva
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| | - M S Li
- Instituto de Física de São Carlos, Universidade de São Paulo, Ave. Trabalhador São Carlense, 400, 13565-590 São Carlos, SP, Brazil
| | - W Wolff
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| | - C L Cesar
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| |
Collapse
|
36
|
Kadyrov AS, Rawlins CM, Stelbovics AT, Bray I, Charlton M. Antihydrogen Formation via Antiproton Scattering with Excited Positronium. PHYSICAL REVIEW LETTERS 2015; 114:183201. [PMID: 26000999 DOI: 10.1103/physrevlett.114.183201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Indexed: 06/04/2023]
Abstract
Utilizing the two-center convergent close-coupling method, we find a several order of magnitude enhancement in the formation of antihydrogen via antiproton scattering with positronium in an excited state over the ground state. The effect is greatest at the lowest energies considered, which encompass those achievable in experiment. This suggests a practical approach to creating neutral antimatter for testing its interaction with gravity and for spectroscopic measurements.
Collapse
Affiliation(s)
- A S Kadyrov
- Curtin Institute for Computation and Department of Physics, Astronomy and Medical Radiation Sciences, Curtin University, Perth, Western Australia 6102, Australia
| | - C M Rawlins
- Curtin Institute for Computation and Department of Physics, Astronomy and Medical Radiation Sciences, Curtin University, Perth, Western Australia 6102, Australia
| | - A T Stelbovics
- Curtin Institute for Computation and Department of Physics, Astronomy and Medical Radiation Sciences, Curtin University, Perth, Western Australia 6102, Australia
| | - I Bray
- Curtin Institute for Computation and Department of Physics, Astronomy and Medical Radiation Sciences, Curtin University, Perth, Western Australia 6102, Australia
| | - M Charlton
- Department of Physics, College of Science, Swansea University, SA28PP, United Kingdom
| |
Collapse
|
37
|
A source of antihydrogen for in-flight hyperfine spectroscopy. Nat Commun 2015; 5:3089. [PMID: 24448273 PMCID: PMC3945878 DOI: 10.1038/ncomms4089] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 12/11/2013] [Indexed: 12/02/2022] Open
Abstract
Antihydrogen, a positron bound to an antiproton, is the simplest antiatom. Its counterpart—hydrogen—is one of the most precisely investigated and best understood systems in physics research. High-resolution comparisons of both systems provide sensitive tests of CPT symmetry, which is the most fundamental symmetry in the Standard Model of elementary particle physics. Any measured difference would point to CPT violation and thus to new physics. Here we report the development of an antihydrogen source using a cusp trap for in-flight spectroscopy. A total of 80 antihydrogen atoms are unambiguously detected 2.7 m downstream of the production region, where perturbing residual magnetic fields are small. This is a major step towards precision spectroscopy of the ground-state hyperfine splitting of antihydrogen using Rabi-like beam spectroscopy. Comparing hydrogen and antihydrogen—its antimatter counterpart—provides important tests of fundamental symmetries in the Standard Model. Kuroda et al. present a source of antihydrogen atoms that may provide high-precision in-flight measurements of their ground-state hyperfine splitting.
Collapse
|
38
|
Aguirre FF, Ordonez CA. Giant cross-magnetic-field steps due to binary collisions between pair particles. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:033103. [PMID: 25871220 DOI: 10.1103/physreve.91.033103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Indexed: 06/04/2023]
Abstract
Giant cross-magnetic-field steps can occur as a result of positron-electron collisions. Within a constant magnetic field (e.g., 1 T), a collision between a positron and an electron can result in a correlated drift across the magnetic field for a continuous range of impact parameters. Within this range, drift distances orders of magnitude larger than that associated with like-charge collisions were observed by computer simulation. Outside of this range, the collisional behavior is similar to that for collisions between particles with the same charge. A theoretical analysis of the phenomenon using center-of-mass and relative coordinates provides insights regarding the occurrence of giant cross-magnetic-field steps.
Collapse
Affiliation(s)
- F F Aguirre
- Department of Physics, University of North Texas, Denton, Texas 76203, USA
| | - C A Ordonez
- Department of Physics, University of North Texas, Denton, Texas 76203, USA
| |
Collapse
|
39
|
Abstract
The creation of cold antihydrogen atoms by the controlled combination of positrons and antiprotons has opened up a new window on fundamental physics. More recently, techniques have been developed that allow some antihydrogen atoms to be created at low enough kinetic energies that they can be held inside magnetic minimum neutral atom traps. With confinement times of many minutes possible, it has become feasible to perform experiments to probe the properties of the antiatom for the first time. We review the experimental progress in this area, outline some of the motivation for studying basic aspects of antimatter physics and provide an outlook of where we might expect this field to go in the coming years.
Collapse
|
40
|
Kuroda N, Mohri A, Torii HA, Nagata Y, Shibata M. First observation of a (1,0) mode frequency shift of an electron plasma at antiproton beam injection. PHYSICAL REVIEW LETTERS 2014; 113:025001. [PMID: 25062195 DOI: 10.1103/physrevlett.113.025001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Indexed: 06/03/2023]
Abstract
The frequency shift of the center-of-mass oscillation, known as the (1,0) mode, of a trapped electron plasma and, furthermore, its time evolution were observed during the cooling of an injected antiproton beam for the first time. Here, antiprotons mixed with the electrons did not follow faster electron oscillations but contributed to the modification of the effective potential. The time evolution of the plasma temperature, deduced from the frequency shift of the excited (3,0) mode, suggested that there was an abnormal energy deposition of the antiproton beam in the electron plasma before thermalization.
Collapse
Affiliation(s)
- N Kuroda
- Institute of Physics, University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan
| | - A Mohri
- Atomic Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - H A Torii
- Institute of Physics, University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan
| | - Y Nagata
- Atomic Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - M Shibata
- Institute of Particle and Nuclear Studies, KEK, Tsukuba, Ibaraki 305-0801, Japan
| |
Collapse
|
41
|
Amole C, Ashkezari MD, Baquero-Ruiz M, Bertsche W, Butler E, Capra A, Cesar CL, Charlton M, Eriksson S, Fajans J, Friesen T, Fujiwara MC, Gill DR, Gutierrez A, Hangst JS, Hardy WN, Hayden ME, Isaac CA, Jonsell S, Kurchaninov L, Little A, Madsen N, McKenna JTK, Menary S, Napoli SC, Nolan P, Olchanski K, Olin A, Povilus A, Pusa P, Rasmussen CØ, Robicheaux F, Sarid E, Silveira DM, So C, Tharp TD, Thompson RI, van der Werf DP, Vendeiro Z, Wurtele JS, Zhmoginov AI, Charman AE. An experimental limit on the charge of antihydrogen. Nat Commun 2014; 5:3955. [PMID: 24892800 PMCID: PMC4279174 DOI: 10.1038/ncomms4955] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 04/24/2014] [Indexed: 11/09/2022] Open
Abstract
The properties of antihydrogen are expected to be identical to those of hydrogen, and any differences would constitute a profound challenge to the fundamental theories of physics. The most commonly discussed antiatom-based tests of these theories are searches for antihydrogen-hydrogen spectral differences (tests of CPT (charge-parity-time) invariance) or gravitational differences (tests of the weak equivalence principle). Here we, the ALPHA Collaboration, report a different and somewhat unusual test of CPT and of quantum anomaly cancellation. A retrospective analysis of the influence of electric fields on antihydrogen atoms released from the ALPHA trap finds a mean axial deflection of 4.1 ± 3.4 mm for an average axial electric field of 0.51 V mm(-1). Combined with extensive numerical modelling, this measurement leads to a bound on the charge Qe of antihydrogen of Q=(-1.3 ± 1.1 ± 0.4) × 10(-8). Here, e is the unit charge, and the errors are from statistics and systematic effects.
Collapse
Affiliation(s)
- C Amole
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada M3J 1P3
| | - M D Ashkezari
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - M Baquero-Ruiz
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - W Bertsche
- 1] School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK [2] The Cockcroft Institute, Daresbury Laboratory, Warrington WA4 4AD, UK
| | - E Butler
- 1] Centre for Cold Matter, Imperial College, London SW7 2BW, UK [2] Physics Department, CERN, CH-1211 Geneva 23, Switzerland
| | - A Capra
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada M3J 1P3
| | - C L Cesar
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - M Charlton
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - S Eriksson
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - J Fajans
- 1] Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA [2] Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - T Friesen
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - M C Fujiwara
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - D R Gill
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - A Gutierrez
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - J S Hangst
- 1] Physics Department, CERN, CH-1211 Geneva 23, Switzerland [2] Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - W N Hardy
- 1] Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1 [2] Canadian Institute of Advanced Research, Toronto, Ontario, Canada M5G 1ZA
| | - M E Hayden
- Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - C A Isaac
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - S Jonsell
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | - L Kurchaninov
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - A Little
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - N Madsen
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - J T K McKenna
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - S Menary
- Department of Physics and Astronomy, York University, Toronto, Ontario, Canada M3J 1P3
| | - S C Napoli
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - P Nolan
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - K Olchanski
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - A Olin
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 2A3
| | - A Povilus
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - P Pusa
- Department of Physics, University of Liverpool, Liverpool L69 7ZE, UK
| | - C Ø Rasmussen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - F Robicheaux
- Department of Physics, Purdue University, West Lafayette, Indiana 47907, USA
| | - E Sarid
- Department of Physics, NRCN-Nuclear Research Center Negev, Beer Sheva IL-84190, Israel
| | - D M Silveira
- Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972, Brazil
| | - C So
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - T D Tharp
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - R I Thompson
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - D P van der Werf
- Department of Physics, College of Science, Swansea University, Swansea SA2 8PP, UK
| | - Z Vendeiro
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| | - J S Wurtele
- 1] Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA [2] Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A I Zhmoginov
- 1] Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA [2] Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - A E Charman
- Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA
| |
Collapse
|
42
|
Hamilton P, Zhmoginov A, Robicheaux F, Fajans J, Wurtele JS, Müller H. Antimatter interferometry for gravity measurements. PHYSICAL REVIEW LETTERS 2014; 112:121102. [PMID: 24724644 DOI: 10.1103/physrevlett.112.121102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Indexed: 06/03/2023]
Abstract
We describe a light-pulse atom interferometer that is suitable for any species of atom and even for electrons and protons as well as their antiparticles, in particular, for testing the Einstein equivalence principle with antihydrogen. The design obviates the need for resonant lasers through far-off resonant Bragg beam splitters and makes efficient use of scarce atoms by magnetic confinement and atom recycling. We expect to reach an initial accuracy of better than 1% for the acceleration of the free fall of antihydrogen, which can be improved to the part-per million level.
Collapse
Affiliation(s)
- Paul Hamilton
- Physics Department, University of California, Berkeley, California 94720, USA
| | - Andrey Zhmoginov
- Physics Department, University of California, Berkeley, California 94720, USA
| | | | - Joel Fajans
- Physics Department, University of California, Berkeley, California 94720, USA
| | - Jonathan S Wurtele
- Physics Department, University of California, Berkeley, California 94720, USA
| | - Holger Müller
- Physics Department, University of California, Berkeley, California 94720, USA
| |
Collapse
|
43
|
|
44
|
Sótér A, Todoroki K, Kobayashi T, Barna D, Horváth D, Hori M. Segmented scintillation detectors with silicon photomultiplier readout for measuring antiproton annihilations. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:023302. [PMID: 24593349 DOI: 10.1063/1.4863648] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The Atomic Spectroscopy and Collisions Using Slow Antiprotons experiment at the Antiproton Decelerator (AD) facility of CERN constructed segmented scintillators to detect and track the charged pions which emerge from antiproton annihilations in a future superconducting radiofrequency Paul trap for antiprotons. A system of 541 cast and extruded scintillator bars were arranged in 11 detector modules which provided a spatial resolution of 17 mm. Green wavelength-shifting fibers were embedded in the scintillators, and read out by silicon photomultipliers which had a sensitive area of 1 × 1 mm(2). The photoelectron yields of various scintillator configurations were measured using a negative pion beam of momentum p ≈ 1 GeV/c. Various fibers and silicon photomultipliers, fiber end terminations, and couplings between the fibers and scintillators were compared. The detectors were also tested using the antiproton beam of the AD. Nonlinear effects due to the saturation of the silicon photomultiplier were seen at high annihilation rates of the antiprotons.
Collapse
Affiliation(s)
- A Sótér
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
| | - K Todoroki
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - T Kobayashi
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - D Barna
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - D Horváth
- Wigner Research Center of Physics, H-1525 Budapest, Hungary
| | - M Hori
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
| |
Collapse
|
45
|
Lodi-Rizzini E, Charlton M, Hayano R, Rotondi A, Venturelli L, Zurlo N. Antihydrogen formation mechanisms. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146605015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
46
|
Stracka S. Real-time Detection of Antihydrogen Annihilations and Applications to Spectroscopy. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20147100126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
47
|
Baalrud SD, Daligault J. Effective potential theory for transport coefficients across coupling regimes. PHYSICAL REVIEW LETTERS 2013; 110:235001. [PMID: 25167502 DOI: 10.1103/physrevlett.110.235001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 05/16/2013] [Indexed: 06/03/2023]
Abstract
A plasma transport theory that spans weak to strong coupling is developed from a binary collision picture, but where the interaction potential is taken to be an effective potential that includes correlation effects and screening self-consistently. This physically motivated approach provides a practical model for evaluating transport coefficients across coupling regimes. The theory is shown to compare well with classical molecular dynamics simulations of temperature relaxation in electron-ion plasmas as well as simulations and experiments of self-diffusion in one-component plasmas. The approach is versatile and can be applied to other transport coefficients as well.
Collapse
Affiliation(s)
- Scott D Baalrud
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA and Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
| | - Jérôme Daligault
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| |
Collapse
|
48
|
Van Noorden R. Bohr's model: Extreme atoms. Nature 2013; 498:22-5. [DOI: 10.1038/498022a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
49
|
Yaakobi O, Caspani L, Clerici M, Vidal F, Morandotti R. Complete energy conversion by autoresonant three-wave mixing in nonuniform media. OPTICS EXPRESS 2013; 21:1623-1632. [PMID: 23389147 DOI: 10.1364/oe.21.001623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Resonant three-wave interactions appear in many fields of physics e.g. nonlinear optics, plasma physics, acoustics and hydrodynamics. A general theory of autoresonant three-wave mixing in a nonuniform media is derived analytically and demonstrated numerically. It is shown that due to the medium nonuniformity, a stable phase-locked evolution is automatically established. For a weak nonuniformity, the efficiency of the energy conversion between the interacting waves can reach almost 100%. One of the potential applications of our theory is the design of highly-efficient optical parametric amplifiers.
Collapse
Affiliation(s)
- O Yaakobi
- INRS-EMT, University of Quebec, 1650 Boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 Canada.
| | | | | | | | | |
Collapse
|
50
|
Dumin YV. Magnetically stimulated diffusion of Rydberg gases. PHYSICAL REVIEW LETTERS 2013; 110:033004. [PMID: 23373921 DOI: 10.1103/physrevlett.110.033004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Indexed: 06/01/2023]
Abstract
The specific kind of diffusion stimulated (rather than suppressed) by the external magnetic field, which was predicted for the first time by Schmelcher and Cederbaum in 1992, is considered here for the case of high-angular-momentum (i.e., approximately "circular") Rydberg atoms. The coefficient of such diffusion was calculated by a purely analytical approach and was found to be very relevant to the experiments on antihydrogen formation.
Collapse
Affiliation(s)
- Yurii V Dumin
- Space Research Institute (IKI) of Russian Academy of Sciences, Moscow, Russia.
| |
Collapse
|