TY - JOUR
T1 - Sensitivity of the NEXT experiment to Xe-124 double electron capture
AU - The NEXT collaboration
AU - Martínez-Lema, G.
AU - Martínez-Vara, M.
AU - Sorel, M.
AU - Adams, C.
AU - Álvarez, V.
AU - Arazi, L.
AU - Arnquist, I. J.
AU - Azevedo, C. D.R.
AU - Bailey, K.
AU - Ballester, F.
AU - Benlloch-Rodríguez, J. M.
AU - Borges, F. I.G.M.
AU - Byrnes, N.
AU - Cárcel, S.
AU - Carrión, J. V.
AU - Cebrián, S.
AU - Church, E.
AU - Conde, C. A.N.
AU - Contreras, T.
AU - Díaz, G.
AU - Díaz, J.
AU - Diesburg, M.
AU - Escada, J.
AU - Esteve, R.
AU - Felkai, R.
AU - Fernandes, A. F.M.
AU - Fernandes, L. M.P.
AU - Ferrario, P.
AU - Ferreira, A. L.
AU - Freitas, E. D.C.
AU - Generowicz, J.
AU - Ghosh, S.
AU - Goldschmidt, A.
AU - Gómez-Cadenas, J. J.
AU - González-Díaz, D.
AU - Guenette, R.
AU - Gutiérrez, R. M.
AU - Haefner, J.
AU - Hafidi, K.
AU - Hauptman, J.
AU - Henriques, C. A.O.
AU - Hernando Morata, J. A.
AU - Herrero, P.
AU - Herrero, V.
AU - Ifergan, Y.
AU - Johnston, S.
AU - Jones, B. J.P.
AU - Kekic, M.
AU - Labarga, L.
AU - Losada, M.
N1 - Publisher Copyright:
© 2021, The Author(s).
PY - 2021/2
Y1 - 2021/2
N2 - 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.]
AB - 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.]
KW - Dark Matter and Double Beta Decay (experiments)
UR - http://www.scopus.com/inward/record.url?scp=85101833596&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85101833596&partnerID=8YFLogxK
U2 - 10.1007/JHEP02(2021)203
DO - 10.1007/JHEP02(2021)203
M3 - Article
AN - SCOPUS:85101833596
SN - 1126-6708
VL - 2021
JO - Journal of High Energy Physics
JF - Journal of High Energy Physics
IS - 2
M1 - 203
ER -