학술논문
Sensitivity of the NEXT experiment to Xe-124 double electron capture
Document Type
Working Paper
Author
Martínez-Lema, G.; Martínez-Vara, M.; Sorel, M.; Adams, C.; Alvarez, V.; Arazi, L.; Arnquist, I. J.; Azevedo, C. D. R; Bailey, K.; Ballester, F.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Byrnes, N.; Cárcel, S.; Carrión, J. V.; Cebrián, S.; Church, E.; Conde, C. A. N.; Contreras, T.; Díaz, G.; Díaz, J.; Diesburg, M.; Escada, J.; Esteve, R.; Felkai, R.; Fernandes, A. F. M.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Generowicz, J.; Ghosh, S.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Guenette, R.; Gutiérrez, R. M.; Haefner, J.; Hafidi, K.; Hauptman, J.; Henriques, C. A. O.; Morata, J. A. Hernando; Herrero, P.; Herrero, V.; Ifergan, Y.; Johnston, S.; Jones, B. J. P.; Kekic, M.; Labarga, L.; Laing, A.; Lebrun, P.; López-March, N.; Losada, M.; Mano, R. D. P.; Martín-Albo, J.; Martínez, A.; McDonald, A. D.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Vidal, J. Muñoz; Novella, P.; Nygren, D. R.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Redwine, A. B.; Renner, J.; Repond, J.; Riordan, S.; Ripoll, L.; García, Y. Rodríguez; Rodríguez, J.; Rogers, L.; Romeo, B.; Romo-Luque, C.; Santos, F. P.; Santos, J. M. F. dos; Simón, A.; Sofka, C.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Usón, A.; Veloso, J. F. C. A.; Webb, R.; Weiss-Babai, R.; White, J. T.; Woodruff, K.; Yahlali, N.
Source
J. High Energ. Phys. 2021, 203 (2021)
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 ($2\nu ECEC$) has been predicted for a number of isotopes, but only observed in $^{78}$Kr, $^{130}$Ba and, recently, $^{124}$Xe. 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, $0\nu ECEC$. Here we report on the current sensitivity of the NEXT-White detector to $^{124}$Xe $2\nu ECEC$ and on the extrapolation to NEXT-100. Using simulated data for the $2\nu ECEC$ signal and real data from NEXT-White operated with $^{124}$Xe-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 $^{124}$Xe and for a 5-year run, a sensitivity to the $2\nu ECEC$ half-life of $6 \times 10^{22}$ y (at 90% confidence level) or better can be reached.
Comment: 23 pages, 13 figures
Comment: 23 pages, 13 figures