학술논문
A High Efficiency Photon Veto for the Light Dark Matter eXperiment
Document Type
Working Paper
Author
Åkesson, Torsten; Blinov, Nikita; Bryngemark, Lene; Colegrove, Owen; Collura, Giulia; Dutta, Craig Dukes. Valentina; 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
Source
Subject
Language
Abstract
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.