A High Efficiency Photon Veto for the Light Dark Matter eXperiment

Fixed-target experiments using primary electron beams can be powerful discovery tools for light dark matter in the sub-GeV mass range. The Light Dark Matter eXperiment (LDMX) is designed to measure missing momentum in high-rate electron fixed-target reactions with beam energies of 4 GeV to 16 GeV. A...

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Bibliographic Details
Published in:arXiv.org 2019-12
Main Authors: Åkesson, Torsten, Blinov, Nikita, Bryngemark, Lene, Colegrove, Owen, Collura, Giulia, Craig Dukes Valentina Dutta, Echenard, Bertrand, Eichlersmith, Thomas, Group, Craig, Hiltbrand, Joshua, Hitlin, David G, Incandela, Joseph, Krnjaic, Gordan, Lazaro, Juan, Li, Amina, Mans, Jeremiah, Masterson, Phillip, McCormick, Jeremy, Moreno, Omar, Mullier, Geoffrey, Nagar, Akshay, Nelson, Timothy, Niendorf, Gavin, Oyang, James, Petersen, Reese, Pöttgen, Ruth, Schuster, Philip, Siegel, Harrison, Toro, Natalia, Tran, Nhan, Whitbeck, Andrew
Format: Article
Language:English
Subjects:
Bremsstrahlung
Dark matter
Electron beams
Luminosity
Momentum
Nuclear reactions
Photons
Rejection
Sensitivity
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Summary:Fixed-target experiments using primary electron beams can be powerful discovery tools for light dark matter in the sub-GeV mass range. The Light Dark Matter eXperiment (LDMX) is designed to measure missing momentum in high-rate electron fixed-target reactions with beam energies of 4 GeV to 16 GeV. A prerequisite for achieving several important sensitivity milestones is the capability to efficiently reject backgrounds associated with few-GeV bremsstrahlung, by twelve orders of magnitude, while maintaining high efficiency for signal. The primary challenge arises from events with photo-nuclear reactions faking the missing-momentum property of a dark matter signal. We present a methodology developed for the LDMX detector concept that is capable of the required rejection. By employing a detailed GEANT4-based model of the detector response, we demonstrate that the sampling calorimetry proposed for LDMX can achieve better than \(10^{-13}\) rejection of few-GeV photons. This suggests that the luminosity-limited sensitivity of LDMX can be realized at 4 GeV and higher beam energies.
ISSN:2331-8422