%0 Journal Article
%T Sensitivity of the NEXT experiment to Xe-124 double electron capture
%A NEXT Collaboration (Martinez-Lema, G. et al
%A Benlloch-Rodriguez, J. M.
%A Carcel, S.
%A Carrion, J. V.
%A Diaz, J.
%A Felkai, R.
%A Kekic, M.
%A Lopez-March, N.
%A Martin-Albo, J.
%A Martinez, A.
%A Martinez-Vara, M.
%A Muñoz Vidal, J.
%A Novella, P.
%A Palmeiro, B.
%A Querol, M.
%A Renner, J.
%A Romo-Luque, C.
%A Sorel, M.
%A Uson, A.
%A Yahlali, N.
%J Journal of High Energy Physics
%D 2021
%V 02
%N 2
%I Springer
%@ 1029-8479
%G English
%F NEXTCollaborationMartinez-Lema_etal2021
%O WOS:000624564800002
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=4749), last updated on Wed, 18 May 2022 07:41:29 +0000
%X 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 EC EC) has been predicted for a number of isotopes, but only observed in Kr-78, Ba-130 and, recently, Xe-124. 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 EC EC. Here we report on the current sensitivity of the NEXT-White detector to Xe-124 2 nu EC EC and on the extrapolation to NEXT-100. Using simulated data for the 2 nu EC EC signal and real data from NEXT-White operated with Xe-124-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 Xe-124 and for a 5-year run, a sensitivity to the 2 nu EC EC half-life of 6 x 10(22) y (at 90% confidence level) or better can be reached.
%K Dark Matter and Double Beta Decay (experiments)
%R 10.1007/JHEP02(2021)203
%U https://arxiv.org/abs/2006.07320
%U https://doi.org/10.1007/JHEP02(2021)203
%P 203-25pp