학술논문
Sensitivity of the NEXT experiment to Xe-124 double electron capture
Document Type
article
Author
Martínez-Lema, G; Martínez-Vara, M; Sorel, M; Adams, C; Álvarez, V; Arazi, L; Arnquist, IJ; Azevedo, CDR; Bailey, K; Ballester, F; Benlloch-Rodríguez, JM; Borges, FIGM; Byrnes, N; Cárcel, S; Carrión, JV; Cebrián, S; Church, E; Conde, CAN; Contreras, T; Díaz, G; Díaz, J; Diesburg, M; Escada, J; Esteve, R; Felkai, R; Fernandes, AFM; Fernandes, LMP; Ferrario, P; Ferreira, AL; Freitas, EDC; Generowicz, J; Ghosh, S; Goldschmidt, A; Gómez-Cadenas, JJ; González-Díaz, D; Guenette, R; Gutiérrez, RM; Haefner, J; Hafidi, K; Hauptman, J; Henriques, CAO; Hernando Morata, JA; Herrero, P; Herrero, V; Ifergan, Y; Johnston, S; Jones, BJP; Kekic, M; Labarga, L; Laing, A; Lebrun, P; López-March, N; Losada, M; Mano, RDP; Martín-Albo, J; Martínez, A; McDonald, AD; Monrabal, F; Monteiro, CMB; Mora, FJ; Muñoz Vidal, J; Novella, P; Nygren, DR; Palmeiro, B; Para, A; Pérez, J; Querol, M; Redwine, AB; Renner, J; Repond, J; Riordan, S; Ripoll, L; Rodríguez García, Y; Rodríguez, J; Rogers, L; Romeo, B; Romo-Luque, C; Santos, FP; dos Santos, JMF; Simón, A; Sofka, C; Stiegler, T; Toledo, JF; Torrent, J; Usón, A; Veloso, JFCA; Webb, R; Weiss-Babai, R; White, JT; Woodruff, K; Yahlali, N
Source
Journal of High Energy Physics. 2021(2)
Subject
Language
Abstract
Double electron capture by proton-rich nuclei is a second-order nuclear process analogous to double beta decay. Despite their similarities, the decay signature is quite different, potentially providing a new channel to measure the hypothesized neutrinoless mode of these decays. The Standard-Model-allowed two-neutrino double electron capture (2νEC EC) has been predicted for a number of isotopes, but only observed in 78Kr, 130Ba and, recently, 124Xe. The sensitivity to this decay establishes a benchmark for the ultimate experimental goal, namely the potential to discover also the lepton-number-violating neutrinoless version of this process, 0νEC EC. Here we report on the current sensitivity of the NEXT-White detector to 124Xe 2νEC EC and on the extrapolation to NEXT-100. Using simulated data for the 2νEC EC signal and real data from NEXT-White operated with 124Xe-depleted gas as background, we define an optimal event selection that maximizes the NEXT-White sensitivity. We estimate that, for NEXT-100 operated with xenon gas isotopically enriched with 1 kg of 124Xe and for a 5-year run, a sensitivity to the 2νEC EC half-life of 6 × 1022 y (at 90% confidence level) or better can be reached. [Figure not available: see fulltext.]