G Adhikari, N Carlin, J J Choi, S Choi, A C Ezeribe, L E França, C Ha, I S Hahn, S J Hollick, E J Jeon, J H Jo, H W Joo, W G Kang, M Kauer, B H Kim, H J Kim, J Kim, K W Kim, S H Kim, S K Kim, W K Kim, Y D Kim, Y H Kim, Y J Ko, D H Lee, E K Lee, H Lee, H S Lee, H Y Lee, I S Lee, J Lee, J Y Lee, M H Lee, S H Lee, S M Lee, Y J Lee, D S Leonard, N T Luan, B B Manzato, R H Maruyama, R J Neal, J A Nikkel, S L Olsen, B J Park, H K Park, H S Park, K S Park, S D Park, R L C Pitta, H Prihtiadi, S J Ra, C Rott, K A Shin, D F F S Cavalcante, A Scarff, N J C Spooner, W G Thompson, L Yang, G H Yu
We search for energetic electron recoil signals induced by boosted dark matter (BDM) from the galactic center using the COSINE-100 array of NaI(Tl) crystal detectors at the Yangyang Underground Laboratory. The signal would be an excess of events with energies above 4 MeV over the well-understood background. Because no excess of events are observed in a 97.7 kg·yr exposure, we set limits on BDM interactions under a variety of hypotheses. Notably, we explored the dark photon parameter space, leading to competitive limits compared to direct dark photon search experiments, particularly for dark photon masses below 4 MeV and considering the invisible decay mode...
November 17, 2023: Physical Review Letters