@article{10902/32911,
year = {2024},
month = {3},
url = {https://hdl.handle.net/10902/32911},
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 ∼7 events per kg-day and electron-equivalent energies of ∼80 eV, whose origin remains unknown.},
organization = {We acknowledge financial support from the following agencies and organizations: NSF through Grant No. NSF PHY-2110585 to the University of Washington and the University of Chicago; the Kavli Institute for Cosmological Physics at the University of Chicago through an endowment from the Kavli Foundation; the U.S. Department of Energy Office of Science through the Dark Matter New Initiatives program; Fermi National Accelerator Laboratory (Contract No. DEAC02-07CH11359); Institut Lagrange de Paris Laboratoire d’Excellence (under Reference No. ANR-10-LABX-63) supported by French state funds managed by the Agence Nationale de la Recherche within the Investissements d’Avenir program under Reference No. ANR-11-IDEX0004-02; Swiss National Science Foundation through Grant No. 200021_153654 and via the Swiss Canton of Zurich; IFCA through Project No. PID2019–109829 GB-I00 funded by MCIN/AEI; Mexico’s Consejo Nacional de Ciencia y Tecnología (Grant No. CF-2023-I-1169) and Dirección General de Asuntos del Personal Académico–Universidad Nacional Autónoma de México (Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica Grant No. IN106322).},
publisher = {American Physical Society},
publisher = {Physical Review D, 2024, 109(6), 062007},
title = {Confirmation of the spectral excess in DAMIC at SNOLAB with skipper CCDs},
author = {Aguilar Arévalo, A. and Castelló Mor, Nuria and Cortabitarte Gutiérrez, Juan and Duarte Campderros, Jorge and Lantero Barreda, Agustín and López Virto, María Amparo and Vila Álvarez, Iván  and Vilar Cortabitarte, Rocío},
}