2
|
Linden T, Zhou B, Beacom JF, Peter AHG, Ng KCY, Tang QW. Evidence for a New Component of High-Energy Solar Gamma-Ray Production. PHYSICAL REVIEW LETTERS 2018; 121:131103. [PMID: 30312037 DOI: 10.1103/physrevlett.121.131103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/23/2018] [Indexed: 06/08/2023]
Abstract
The observed multi-GeV γ-ray emission from the solar disk-sourced by hadronic cosmic rays interacting with gas and affected by complex magnetic fields-is not understood. Utilizing an improved analysis of the Fermi-LAT data that includes the first resolved imaging of the disk, we find strong evidence that this emission is produced by two separate mechanisms. Between 2010 and 2017 (the rise to and fall from solar maximum), the γ-ray emission was dominated by a polar component. Between 2008 and 2009 (solar minimum) this component remained present, but the total emission was instead dominated by a new equatorial component with a brighter flux and harder spectrum. Most strikingly, although six γ rays above 100 GeV were observed during the 1.4 yr of solar minimum, none were observed during the next 7.8 yr. These features, along with a 30-50 GeV spectral dip which will be discussed in a companion paper, were not anticipated by theory. To understand the underlying physics, Fermi-LAT and HAWC observations of the imminent cycle 25 solar minimum are crucial.
Collapse
Affiliation(s)
- Tim Linden
- Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, Ohio 43210, USA
| | - Bei Zhou
- Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, Ohio 43210, USA
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - John F Beacom
- Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, Ohio 43210, USA
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Astronomy, The Ohio State University, Columbus, Ohio 43210, USA
| | - Annika H G Peter
- Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, Ohio 43210, USA
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Astronomy, The Ohio State University, Columbus, Ohio 43210, USA
| | - Kenny C Y Ng
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Qing-Wen Tang
- Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, Ohio 43210, USA
- Department of Physics, Nanchang University, Nanchang 330031, China
| |
Collapse
|
3
|
Alvis SI, Arnquist IJ, Avignone FT, Barabash AS, Barton CJ, Bertrand FE, Brudanin V, Busch M, Buuck M, Caldwell TS, Chan YD, Christofferson CD, Chu PH, Cuesta C, Detwiler JA, Dunagan C, Efremenko Y, Ejiri H, Elliott SR, Gilliss T, Giovanetti GK, Green MP, Gruszko J, Guinn IS, Guiseppe VE, Haufe CR, Hehn L, Henning R, Hoppe EW, Howe MA, Konovalov SI, Kouzes RT, Lopez AM, Martin RD, Massarczyk R, Meijer SJ, Mertens S, Myslik J, O'Shaughnessy C, Othman G, Pettus W, Poon AWP, Radford DC, Rager J, Reine AL, Rielage K, Robertson RGH, Ruof NW, Shanks B, Shirchenko M, Suriano AM, Tedeschi D, Varner RL, Vasilyev S, Vorren K, White BR, Wilkerson JF, Wiseman C, Xu W, Yakushev E, Yu CH, Yumatov V, Zhitnikov I, Zhu BX. First Limit on the Direct Detection of Lightly Ionizing Particles for Electric Charge as Low as e/1000 with the Majorana Demonstrator. PHYSICAL REVIEW LETTERS 2018; 120:211804. [PMID: 29883176 DOI: 10.1103/physrevlett.120.211804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/23/2018] [Indexed: 06/08/2023]
Abstract
The Majorana Demonstrator is an ultralow-background experiment searching for neutrinoless double-beta decay in ^{76}Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. Free, relativistic, lightly ionizing particles with an electrical charge less than e are forbidden by the standard model but predicted by some of its extensions. If such particles exist, they might be detected in the Majorana Demonstrator by searching for multiple-detector events with individual-detector energy depositions down to 1 keV. This search is background-free, and no candidate events have been found in 285 days of data taking. New direct-detection limits are set for the flux of lightly ionizing particles for charges as low as e/1000.
Collapse
Affiliation(s)
- S I Alvis
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - I J Arnquist
- Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - F T Avignone
- Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - A S Barabash
- National Research Center "Kurchatov Institute" Institute for Theoretical and Experimental Physics, Moscow 117218, Russia
| | - C J Barton
- Department of Physics, University of South Dakota, Vermillion, South Dakota 57069, USA
| | - F E Bertrand
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - V Brudanin
- Joint Institute for Nuclear Research, Dubna 141980, Russia
| | - M Busch
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
| | - M Buuck
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - T S Caldwell
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - Y-D Chan
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - C D Christofferson
- South Dakota School of Mines and Technology, Rapid City, South Dakota 57701, USA
| | - P-H Chu
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C Cuesta
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - J A Detwiler
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - C Dunagan
- South Dakota School of Mines and Technology, Rapid City, South Dakota 57701, USA
| | - Yu Efremenko
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916, USA
| | - H Ejiri
- Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - S R Elliott
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - T Gilliss
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - G K Giovanetti
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - M P Green
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - J Gruszko
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - I S Guinn
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - V E Guiseppe
- Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA
| | - C R Haufe
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - L Hehn
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - R Henning
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - E W Hoppe
- Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - M A Howe
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - S I Konovalov
- National Research Center "Kurchatov Institute" Institute for Theoretical and Experimental Physics, Moscow 117218, Russia
| | - R T Kouzes
- Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - A M Lopez
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37916, USA
| | - R D Martin
- Department of Physics, Engineering Physics and Astronomy, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - R Massarczyk
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S J Meijer
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - S Mertens
- Max-Planck-Institut für Physik, München 80805, Germany
- Physik Department, Technische Universität, München 85748, Germany
| | - J Myslik
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - C O'Shaughnessy
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - G Othman
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - W Pettus
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - A W P Poon
- Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - D C Radford
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - J Rager
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - A L Reine
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - K Rielage
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - R G H Robertson
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - N W Ruof
- Center for Experimental Nuclear Physics and Astrophysics, and Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - B Shanks
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - M Shirchenko
- Joint Institute for Nuclear Research, Dubna 141980, Russia
| | - A M Suriano
- South Dakota School of Mines and Technology, Rapid City, South Dakota 57701, USA
| | - D Tedeschi
- Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA
| | - R L Varner
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - S Vasilyev
- Joint Institute for Nuclear Research, Dubna 141980, Russia
| | - K Vorren
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - B R White
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J F Wilkerson
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA
- Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27514, USA
| | - C Wiseman
- Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA
| | - W Xu
- Department of Physics, University of South Dakota, Vermillion, South Dakota 57069, USA
| | - E Yakushev
- Joint Institute for Nuclear Research, Dubna 141980, Russia
| | - C-H Yu
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - V Yumatov
- National Research Center "Kurchatov Institute" Institute for Theoretical and Experimental Physics, Moscow 117218, Russia
| | - I Zhitnikov
- Joint Institute for Nuclear Research, Dubna 141980, Russia
| | - B X Zhu
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| |
Collapse
|