1. Confirmation of the spectral excess in DAMIC at SNOLAB with skipper CCDs
- Author
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Aguilar-Arevalo, A., Arnquist, I., Avalos, N., Barak, L., Baxter, D., Bertou, X., Bloch, I. M., Botti, A. M., Cababie, M., Cancelo, G., Castelló-Mor, N., Cervantes-Vergara, B. A., Chavarria, A. E., Cortabitarte-Gutiérrez, J., Crisler, M., Cuevas-Zepeda, J., Dastgheibi-Fard, A., De Dominicis, C., Deligny, O., Drlica-Wagner, A., Duarte-Campderros, J., D'Olivo, J. C., Essig, R., Estrada, E., Estrada, J., Etzion, E., Favela-Perez, F., Gadola, N., Gaïor, R., Holland, S. E., Hossbach, T., Iddir, L., Kilminster, B., Korn, Y., Lantero-Barreda, A., Lawson, I., Lee, S., Letessier-Selvon, A., Loaiza, P., Lopez-Virto, A., Luoma, S., Marrufo-Villalpando, E., McGuire, K. J., Moroni, G. F., Munagavalasa, S., Norcini, D., Orly, A., Papadopoulos, G., Paul, S., Perez, S. E., Piers, A., Privitera, P., Robmann, P., Rodrigues, D., Saffold, N. A., Scorza, S., Settimo, M., Singal, A., Smida, R., Sofo-Haro, M., Stefanazzi, L., Stifter, K., Tiffenberg, J., Traina, M., Uemura, S., Vila, I., Vilar, R., Volansky, T., Warot, G., Yajur, R., Yu, T-T., and Zopounidis, J-P.
- Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics ,High Energy Physics - Experiment ,Nuclear Experiment - Abstract
We present results from a 3.25 kg-day target exposure of two silicon charge-coupled devices (CCDs), each with 24 megapixels and skipper readout, deployed in the DAMIC setup at SNOLAB. With a reduction in pixel readout noise of a factor of 10 relative to the previous detector, we investigate the excess population of low-energy events in the CCD bulk previously observed above expected backgrounds. We address the dominant systematic uncertainty of the previous analysis through a depth fiducialization designed to reject surface backgrounds on the CCDs. The measured bulk ionization spectrum confirms the presence of an excess population of low-energy events in the CCD target with characteristic rate of ${\sim}7$ events per kg-day and electron-equivalent energies of ${\sim}80~$eV, whose origin remains unknown., Comment: 8 pages, 4 figures
- Published
- 2023
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