2026/07/29 by D. Auguste, A. S. Barabash, G. Benato +42
Physics and Astronomy · #nucl-ex #physics.ins-det
16 pages, 14 figures and 1 table; prepared for submission to EPJC
arxiv created 2026/07/29 · arxiv updated 2026/07/30
The CROSS experiment to search for neutrinoless double-beta (0ν2β) decay in 100Mo with the help of an array of scintillating cryogenic calorimeters, containing 4.9 kg of 100Mo, has been ongoing in a low-background setup at the Canfranc underground laboratory (Spain) since mid-November 2025. In this paper, we present the construction of the CROSS detector and the description of Geant4-based Monte Carlo simulations of expected background in the region of interest. The simulations predict the background index in a 100-keV-wide interval centered at the Q-value of 100Mo (3034 keV) on the level of 3.2(5) × 10-3 cnts/keV/kg/yr. Taking into account an 18% deadtime induced by the muon veto cut and a typical 90% duty cycle of the facility, such background level would allow to reach the world-leading sensitivity to 100Mo 0ν2β decay (lim T1/2 ∼ 4 × 1024 yr) in 1 year of data taking. Considering conservatively a factor 3 (10) worse background index due to unpredictable radioactive contamination of construction materials and/or detector performance, a 2-yr-long operation of the CROSS array would be still compatible with the best (competitive) sensitivity to 0ν2β decay in 100Mo.