Investigating the sources of low-energy events in a SuperCDMS-HVeV detector
Creators: name: SuperCDMS Collaboration
name: Albakry, M. F.
name: Alkhatib, I.
name: Amaral, D. W. P.
name: Aralis, T.
name: Aramaki, T.
name: Arnquist, I. J.
name: Langroudy, I. Ataee
name: Azadbakht, E.
name: Banik, S.
name: Bathurst, C.
name: Bauer, D. A.
name: Bhattacharyya, R.
name: Brink, P. L.
name: Bunker, R.
name: Cabrera, B.
name: Calkins, R.
name: Cameron, R. A.
name: Cartaro, C.
name: Cerdeño, D. G.
name: Chang, Y. -Y.
name: Chaudhuri, M.
name: Chen, R.
name: Chott, N.
name: Cooley, J.
name: Coombes, H.
name: Corbett, J.
name: Cushman, P.
name: De Brienne, F.
name: Dharani, S.
name: di Vacri, M. L.
name: Diamond, M. D.
name: Fascione, E.
name: Figueroa-Feliciano, E.
name: Fink, C. W.
name: Fouts, K.
name: Fritts, M.
name: Gerbier, G.
name: Germond, R.
name: Ghaith, M.
name: Golwala, S. R.
name: Hall, J.
name: Hassan, N.
name: Hines, B. A.
name: Hollister, M. I.
name: Hong, Z.
name: Hoppe, E. W.
name: Hsu, L.
name: Huber, M. E.
name: Iyer, V.
name: Jastram, A.
name: Kashyap, V. K. S.
name: Kelsey, M. H.
name: Kubik, A.
name: Kurinsky, N. A.
name: Lawrence, R. E.
name: Lee, M.
name: Li, A.
name: Liu, J.
name: Liu, Y.
name: Loer, B.
name: Asamar, E. Lopez
name: Lukens, P.
name: MacFarlane, D. B.
name: Mahapatra, R.
name: Mandic, V.
name: Mast, N.
name: Mayer, A. J.
name: Theenhausen, H. Meyer zu
name: Michaud, É.
name: Michielin, E.
name: Mirabolfathi, N.
name: Mohanty, B.
name: Nagorny, S.
name: Nelson, J.
name: Neog, H.
name: Novati, V.
name: Orrell, J. L.
name: Osborne, M. D.
name: Oser, S. M.
name: Page, W. A.
name: Partridge, R.
name: Pedreros, D. S.
name: Podviianiuk, R.
name: Ponce, F.
name: Poudel, S.
name: Pradeep, A.
name: Pyle, M.
name: Rau, W.
name: Reid, E.
name: Ren, R.
name: Reynolds, T.
name: Roberts, A.
name: Robinson, A. E.
name: Saab, T.
name: Sadoulet, B.
name: Saikia, I.
name: Sander, J.
name: Sattari, A.
name: Schmidt, B.
name: Schnee, R. W.
name: Scorza, S.
name: Serfass, B.
name: Poudel, S. S.
name: Sincavage, D. J.
name: Stanford, C.
name: Street, J.
name: Sun, H.
name: Thasrawala, F. K.
name: Toback, D.
name: Underwood, R.
name: Verma, S.
name: Villano, A. N.
name: von Krosigk, B.
name: Watkins, S. L.
name: Wen, O.
name: Williams, Z.
name: Wilson, M. J.
name: Winchell, J.
name: Wykoff, K.
name: Yellin, S.
name: Young, B. A.
name: Yu, T. C.
name: Zatschler, B.
name: Zatschler, S.
name: Zaytsev, A.
name: Zhang, E.
name: Zheng, L.
name: Zuber, S.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Recent experiments searching for sub-GeV/$c^2$ dark matter have observed event excesses close to their respective energy thresholds. Although specific to the individual technologies, the measured excess event rates have been consistently reported at or below event energies of a few-hundred eV, or with charges of a few electron-hole pairs. In the present work, we operated a 1-gram silicon SuperCDMS-HVeV detector at three voltages across the crystal (0 V, 60 V and 100 V). The 0 V data show an excess of events in the tens of eV region. Despite this event excess, we demonstrate the ability to set a competitive exclusion limit on the spin-independent dark matter--nucleon elastic scattering cross section for dark matter masses of $\mathcal{O}(100)$ MeV/$c^2$, enabled by operation of the detector at 0 V potential and achievement of a very low $\mathcal{O}(10)$ eV threshold for nuclear recoils. Comparing the data acquired at 0 V, 60 V and 100 V potentials across the crystal, we investigated possible sources of the unexpected events observed at low energy. The data indicate that the dominant contribution to the excess is consistent with a hypothesized luminescence from the printed circuit boards used in the detector holder.