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Alekhin S, Altmannshofer W, Asaka T, Batell B, Bezrukov F, Bondarenko K, Boyarsky A, Choi KY, Corral C, Craig N, Curtin D, Davidson S, de Gouvêa A, Dell'Oro S, deNiverville P, Bhupal Dev PS, Dreiner H, Drewes M, Eijima S, Essig R, Fradette A, Garbrecht B, Gavela B, Giudice GF, Goodsell MD, Gorbunov D, Gori S, Grojean C, Guffanti A, Hambye T, Hansen SH, Helo JC, Hernandez P, Ibarra A, Ivashko A, Izaguirre E, Jaeckel J, Jeong YS, Kahlhoefer F, Kahn Y, Katz A, Kim CS, Kovalenko S, Krnjaic G, Lyubovitskij VE, Marcocci S, Mccullough M, McKeen D, Mitselmakher G, Moch SO, Mohapatra RN, Morrissey DE, Ovchynnikov M, Paschos E, Pilaftsis A, Pospelov M, Reno MH, Ringwald A, Ritz A, Roszkowski L, Rubakov V, Ruchayskiy O, Schienbein I, Schmeier D, Schmidt-Hoberg K, Schwaller P, Senjanovic G, Seto O, Shaposhnikov M, Shchutska L, Shelton J, Shrock R, Shuve B, Spannowsky M, Spray A, Staub F, Stolarski D, Strassler M, Tello V, Tramontano F, Tripathi A, Tulin S, Vissani F, Winkler MW, Zurek KM. A facility to search for hidden particles at the CERN SPS: the SHiP physics case. Rep Prog Phys 2016; 79:124201. [PMID: 27775925 DOI: 10.1088/0034-4885/79/12/124201] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
This paper describes the physics case for a new fixed target facility at CERN SPS. The SHiP (search for hidden particles) experiment is intended to hunt for new physics in the largely unexplored domain of very weakly interacting particles with masses below the Fermi scale, inaccessible to the LHC experiments, and to study tau neutrino physics. The same proton beam setup can be used later to look for decays of tau-leptons with lepton flavour number non-conservation, [Formula: see text] and to search for weakly-interacting sub-GeV dark matter candidates. We discuss the evidence for physics beyond the standard model and describe interactions between new particles and four different portals-scalars, vectors, fermions or axion-like particles. We discuss motivations for different models, manifesting themselves via these interactions, and how they can be probed with the SHiP experiment and present several case studies. The prospects to search for relatively light SUSY and composite particles at SHiP are also discussed. We demonstrate that the SHiP experiment has a unique potential to discover new physics and can directly probe a number of solutions of beyond the standard model puzzles, such as neutrino masses, baryon asymmetry of the Universe, dark matter, and inflation.
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Affiliation(s)
- Sergey Alekhin
- Deutsches Elektronensynchrotron DESY, Platanenallee 6, D-15738 Zeuthen, Germany. Institute for High Energy Physics, 142281 Protvino, Moscow region, Russia
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Dasgupta B, Kopp J, Schwaller P. Photons, photon jets, and dark photons at 750 GeV and beyond. Eur Phys J C Part Fields 2016; 76:277. [PMID: 28280432 PMCID: PMC5321233 DOI: 10.1140/epjc/s10052-016-4127-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 05/04/2016] [Indexed: 06/06/2023]
Abstract
In new physics searches involving photons at the LHC, one challenge is to distinguish scenarios with isolated photons from models leading to "photon jets". For instance, in the context of the 750 GeV diphoton excess, it was pointed out that a true diphoton resonance [Formula: see text] can be mimicked by a process of the form [Formula: see text], where S is a new scalar with a mass of 750 GeV and a is a light pseudoscalar decaying to two collinear photons. Photon jets can be distinguished from isolated photons by exploiting the fact that a large fraction of photons convert to an [Formula: see text] pair inside the inner detector. In this note, we quantify this discrimination power, and we study how the sensitivity of future searches differs for photon jets compared to isolated photons. We also investigate how our results depend on the lifetime of the particle(s) decaying to the photon jet. Finally, we discuss the extension to [Formula: see text], where there are no photons at all but the dark photon [Formula: see text] decays to [Formula: see text] pairs. Our results will be useful in future studies of the putative 750 GeV signal, but also more generally in any new physics search involving hard photons.
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Affiliation(s)
- Basudeb Dasgupta
- Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, 400005 India
| | - Joachim Kopp
- PRISMA Cluster of Excellence, Mainz Institute for Theoretical Physics, Johannes Gutenberg University, Staudingerweg 7, Mainz, 55099 Germany
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Abstract
In this work, we show that a large class of models with a composite dark sector undergo a strong first order phase transition in the early Universe, which could lead to a detectable gravitational wave signal. We summarize the basic conditions for a strong first order phase transition for SU(N) dark sectors with n_{f} flavors, calculate the gravitational wave spectrum and show that, depending on the dark confinement scale, it can be detected at eLISA or in pulsar timing array experiments. The gravitational wave signal provides a unique test of the gravitational interactions of a dark sector, and we discuss the complementarity with conventional searches for new dark sectors. The discussion includes the twin Higgs and strongly interacting massive particle models as well as symmetric and asymmetric composite dark matter scenarios.
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Zehnder S, Schwaller P, von Arx U, Bucher G, Neuenschwander B. Micro structuring of transparent materials with NIR ns-laser pulses. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.phpro.2011.03.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Schwaller P, Aeberhard M, Nelis T, Fischer A, Thapliyal R, Michler J. Rapid depth profiling of lead zirconate titanate (PZT) thin films by pulsed glow-discharge optical emission spectroscopy. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2264] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ruffieux P, Groning O, Schwaller P, Schlapbach L, Groning P. Hydrogen atoms cause long-range electronic effects on graphite. Phys Rev Lett 2000; 84:4910-4913. [PMID: 10990829 DOI: 10.1103/physrevlett.84.4910] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/1999] [Indexed: 05/23/2023]
Abstract
We report on long-range electronic effects caused by hydrogen-carbon interaction at the graphite surface. Two types of defects could be distinguished with a combined mode of scanning tunneling microscopy and atomic force microscopy: chemisorption of hydrogen on the basal plane of graphite and atomic vacancy formation. Both types show a (sqrt[3]xsqrt[3])R30 degrees superlattice in the local density of states but have a different topographic structure. The range of modifications in the electronic structure, of fundamental importance for electronic devices based on carbon nanostructures, has been found to be of the order of 20-25 lattice constants.
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Affiliation(s)
- P Ruffieux
- Physics Department, University of Fribourg, Perolles, CH-1700 Fribourg, Switzerland
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Schwaller P, Groning P, Schneuwly A, Boschung P, Muller E, Blanc M, Schlapbach L. Surface and friction characterization by thermoelectric measurements during ultrasonic friction processes. Ultrasonics 2000; 38:212-214. [PMID: 10829660 DOI: 10.1016/s0041-624x(99)00062-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Even though friction is one of the oldest problems in physics many aspects of friction processes are not clear today. We present an experimental setup, which permits the study of tribological systems by measuring the dissipated heat at the interface of two surfaces during a friction process with a time resolution of 1 ms. The apparatus is based on a standard ultrasonic wire-bond machine used in semiconductor industries to connect the internal semiconductor die to the external leads, but the standard bond wire is replaced by a thermocouple. To demonstrate the ability of the apparatus it will be shown that bond substrates used in semiconductor industries can be unequivocally characterized.
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Affiliation(s)
- P Schwaller
- Institut de Physique, Universite de Fribourg, Switzerland.
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Affiliation(s)
- P. Gröning
- Physics Department, University of Fribourg, Pérolles, CH‐1700 Fribourg, Switzerland
| | - P. Schwaller
- Physics Department, University of Fribourg, Pérolles, CH‐1700 Fribourg, Switzerland
| | - A. Schneuwly
- Physics Department, University of Fribourg, Pérolles, CH‐1700 Fribourg, Switzerland
| | - L. Schlapbach
- Physics Department, University of Fribourg, Pérolles, CH‐1700 Fribourg, Switzerland
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Aebi P, Kreutz TJ, Osterwalder J, Fasel R, Schwaller P, Schlapbach L. k-space mapping of majority and minority bands on the Fermi surface of Nickel below and above the Curie temperature. Phys Rev Lett 1996; 76:1150-1153. [PMID: 10061646 DOI: 10.1103/physrevlett.76.1150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Aebi P, Osterwalder J, Schwaller P, Schlapbach L, Shimoda M, Mochiku T, Kadowaki K. Complete Fermi surface mapping of Bi2Sr2CaCu2O8+x(001): Coexistence of short range antiferromagnetic correlations and metallicity in the same phase. Phys Rev Lett 1994; 72:2757-2760. [PMID: 10055969 DOI: 10.1103/physrevlett.72.2757] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Schwaller P, Aebi P, Osterwalder J, Schlapbach L, Shimoda M, Mochiku T, Kadowaki K. Local epitaxy of Ag on Bi2Sr2CaCu2O8+x(001). Phys Rev B Condens Matter 1993; 48:6732-6735. [PMID: 10009245 DOI: 10.1103/physrevb.48.6732] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Schwaller P, Schmidt-Lorenz W. La flore microbienne de quatre eaux minérales non gazéifiées et mises en bouteilles 2ème communication: Les Pseudomonas et autres bactéries à gram négatif — Composition fine de la flore. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/s0721-9571(81)80039-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Schwaller P, Schmidt-Lorenz W. Flore microbienne de quatre eaux minérales non gazéifiées et mises en bouteilles I. Dénombrement de colonies, composition grossière de la flore, et caractères du groupe des bactéries gram négatif pigmentées en jaune. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/s0172-5564(80)80027-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
Submillimeter wave gas lasers are characterized by low Fresnel numbers and by gain widths smaller than the mode separations. This allows interferometry of laser emissions and resonator modes with the aid of the laser resonator. The theory of Bergstein and Schachter on modes occurring in resonators with low Fresnel numbers is compared with the experimental data obtained by laser resonator interferometry. The influence of the tilt of a resonator mirror on the intensity of the laser emission is measured for different modes.
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Affiliation(s)
- P Schwaller
- Laboratorium für Festkörperphysikder Eidgenössischen Technischen Hochschule, Zürich, Switzerland
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