Double-Weak Decays of $^{124}$Xe and $^{136}$Xe in the XENON1T and XENONnT Experiments
Creators: name: Aprile, E.
name: Abe, K.
name: Agostini, F.
name: Maouloud, S. Ahmed
name: Alfonsi, M.
name: Althueser, L.
name: Andrieu, B.
name: Angelino, E.
name: Angevaare, J. R.
name: Antochi, V. C.
name: Martin, D. Antón
name: Arneodo, F.
name: Baudis, L.
name: Baxter, A. L.
name: Bellagamba, L.
name: Biondi, R.
name: Bismark, A.
name: Brown, A.
name: Bruenner, S.
name: Bruno, G.
name: Budnik, R.
name: Cai, C.
name: Capelli, C.
name: Cardoso, J. M. R.
name: Cichon, D.
name: Clark, M.
name: Colijn, A. P.
name: Conrad, J.
name: Cuenca-García, J. J.
name: Cussonneau, J. P.
name: D'Andrea, V.
name: Decowski, M. P.
name: Di Gangi, P.
name: Di Pede, S.
name: Di Giovanni, A.
name: Di Stefano, R.
name: Diglio, S.
name: Eitel, K.
name: Elykov, A.
name: Farrell, S.
name: Ferella, A. D.
name: Fischer, H.
name: Fulgione, W.
name: Gaemers, P.
name: Gaior, R.
name: Rosso, A. Gallo
name: Galloway, M.
name: Gao, F.
name: Glade-Beucke, R.
name: Grandi, L.
name: Grigat, J.
name: Guida, M.
name: Higuera, A.
name: Hils, C.
name: Hoetzsch, L.
name: Howlett, J.
name: Iacovacci, M.
name: Itow, Y.
name: Jakob, J.
name: Joerg, F.
name: Joy, A.
name: Kato, N.
name: Kara, M.
name: Kavrigin, P.
name: Kazama, S.
name: Kobayashi, M.
name: Koltman, G.
name: Kopec, A.
name: Landsman, H.
name: Lang, R. F.
name: Levinson, L.
name: Li, I.
name: Li, S.
name: Liang, S.
name: Lindemann, S.
name: Lindner, M.
name: Liu, K.
name: Loizeau, J.
name: Lombardi, F.
name: Long, J.
name: Lopes, J. A. M.
name: Ma, Y.
name: Macolino, C.
name: Mahlstedt, J.
name: Mancuso, A.
name: Manenti, L.
name: Manfredini, A.
name: Marignetti, F.
name: Undagoitia, T. Marrodán
name: Martens, K.
name: Masbou, J.
name: Masson, D.
name: Masson, E.
name: Mastroianni, S.
name: Messina, M.
name: Miuchi, K.
name: Mizukoshi, K.
name: Molinario, A.
name: Moriyama, S.
name: Morå, K.
name: Mosbacher, Y.
name: Murra, M.
name: Müller, J.
name: Ni, K.
name: Oberlack, U.
name: Paetsch, B.
name: Palacio, J.
name: Peres, R.
name: Pienaar, J.
name: Pierre, M.
name: Pizzella, V.
name: Plante, G.
name: Qi, J.
name: Qin, J.
name: García, D. Ramírez
name: Reichard, S.
name: Rocchetti, A.
name: Rupp, N.
name: Sanchez, L.
name: Santos, J. M. F. dos
name: Sarnoff, I.
name: Sartorelli, G.
name: Schreiner, J.
name: Schulte, D.
name: Schulte, P.
name: Eißing, H. Schulze
name: Schumann, M.
name: Lavina, L. Scotto
name: Selvi, M.
name: Semeria, F.
name: Shagin, P.
name: Shi, S.
name: Shockley, E.
name: Silva, M.
name: Simgen, H.
name: Takeda, A.
name: Tan, P. -L.
name: Terliuk, A.
name: Thers, D.
name: Toschi, F.
name: Trinchero, G.
name: Tunnell, C.
name: Tönnies, F.
name: Valerius, K.
name: Volta, G.
name: Wei, Y.
name: Weinheimer, C.
name: Weiss, M.
name: Wenz, D.
name: Wittweg, C.
name: Wolf, T.
name: Xu, Z.
name: Yamashita, M.
name: Yang, L.
name: Ye, J.
name: Yuan, L.
name: Zavattini, G.
name: Zerbo, S.
name: Zhong, M.
name: Zhu, T.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We present results on the search for double-electron capture ($2ν\text{ECEC}$) of $^{124}$Xe and neutrinoless double-$β$ decay ($0νββ$) of $^{136}$Xe in XENON1T. We consider captures from the K- up to the N-shell in the $2ν\text{ECEC}$ signal model and measure a total half-life of $T_{1/2}^{2ν\text{ECEC}}=(1.1\pm0.2_\text{stat}\pm0.1_\text{sys})\times 10^{22}\;\text{yr}$ with a $0.87\;\text{kg}\times\text{yr}$ isotope exposure. The statistical significance of the signal is $7.0\,σ$. We use XENON1T data with $36.16\;\text{kg}\times\text{yr}$ of $^{136}$Xe exposure to search for $0νββ$. We find no evidence of a signal and set a lower limit on the half-life of $T_{1/2}^{0νββ} &gt; 1.2 \times 10^{24}\;\text{yr}\; \text{at}\; 90\,\%\;\text{CL}$. This is the best result from a dark matter detector without an enriched target to date. We also report projections on the sensitivity of XENONnT to $0νββ$. Assuming a $275\;\text{kg}\times\text{yr}$ $^{136}$Xe exposure, the expected sensitivity is $T_{1/2}^{0νββ} &gt; 2.1 \times 10^{25}\;\text{yr}\; \text{at}\; 90\,\%\;\text{CL}$, corresponding to an effective Majorana mass range of $\langle m_{ββ} \rangle &lt; (0.19 - 0.59)\;\text{eV/c}^2$.
description: 23 pages, 14 figures, 9 tables, version accepted for publication in Phys. Rev. C