Two-neutrino double electron capture of $^{124}$Xe in the first LUX-ZEPLIN exposure
Creators: name: Aalbers, J.
name: Akerib, D. S.
name: Musalhi, A. K. Al
name: Alder, F.
name: Amarasinghe, C. S.
name: Ames, A.
name: Anderson, T. J.
name: Angelides, N.
name: Araújo, H. M.
name: Armstrong, J. E.
name: Arthurs, M.
name: Baker, A.
name: Balashov, S.
name: Bang, J.
name: Bargemann, J. W.
name: Barillier, E. E.
name: Beattie, K.
name: Bhatti, A.
name: Biekert, A.
name: Biesiadzinski, T. P.
name: Birch, H. J.
name: Bishop, E.
name: Blockinger, G. M.
name: Boxer, B.
name: Brew, C. A. J.
name: Brás, P.
name: Burdin, S.
name: Buuck, M.
name: Carmona-Benitez, M. C.
name: Carter, M.
name: Chawla, A.
name: Chen, H.
name: Chin, Y. T.
name: Chott, N. I.
name: Converse, M. V.
name: Coronel, R.
name: Cottle, A.
name: Cox, G.
name: Curran, D.
name: Dahl, C. E.
name: David, A.
name: Delgaudio, J.
name: Dey, S.
name: de Viveiros, L.
name: Di Felice, L.
name: Ding, C.
name: Dobson, J. E. Y.
name: Druszkiewicz, E.
name: Dubey, S.
name: Eriksen, S. R.
name: Fan, A.
name: Fearon, N. M.
name: Fieldhouse, N.
name: Fiorucci, S.
name: Flaecher, H.
name: Fraser, E. D.
name: Fruth, T. M. A.
name: Gaitskell, R. J.
name: Geffre, A.
name: Genovesi, J.
name: Ghag, C.
name: Gibbons, R.
name: Gokhale, S.
name: Green, J.
name: van der Grinten, M. G. D.
name: Haiston, J. J.
name: Hall, C. R.
name: Han, S.
name: Hartigan-O'Connor, E.
name: Haselschwardt, S. J.
name: Hernandez, M. A.
name: Hertel, S. A.
name: Heuermann, G.
name: Homenides, G. J.
name: Horn, M.
name: Huang, D. Q.
name: Hunt, D.
name: Jacquet, E.
name: James, R. S.
name: Johnson, J.
name: Kaboth, A. C.
name: Kamaha, A. C.
name: Kannichankandy, M.
name: Khaitan, D.
name: Khazov, A.
name: Khurana, I.
name: Kim, J.
name: Kim, Y. D.
name: Kingston, J.
name: Kirk, R.
name: Kodroff, D.
name: Korley, L.
name: Korolkova, E. V.
name: Kraus, H.
name: Kravitz, S.
name: Kreczko, L.
name: Kudryavtsev, V. A.
name: Leonard, D. S.
name: Lesko, K. T.
name: Levy, C.
name: Lin, J.
name: Lindote, A.
name: Lippincott, W. H.
name: Lopes, M. I.
name: Lorenzon, W.
name: Lu, C.
name: Luitz, S.
name: Majewski, P. A.
name: Manalaysay, A.
name: Mannino, R. L.
name: Maupin, C.
name: McCarthy, M. E.
name: McDowell, G.
name: McKinsey, D. N.
name: McLaughlin, J.
name: McLaughlin, J. B.
name: McMonigle, R.
name: Mizrachi, E.
name: Monte, A.
name: Monzani, M. E.
name: Morrison, E.
name: Mount, B. J.
name: Murdy, M.
name: Murphy, A. St. J.
name: Naylor, A.
name: Nelson, H. N.
name: Neves, F.
name: Nguyen, A.
name: O'Brien, C. L.
name: Olcina, I.
name: Oliver-Mallory, K. C.
name: Orpwood, J.
name: Oyulmaz, K. Y
name: Palladino, K. J.
name: Palmer, J.
name: Pannifer, N. J.
name: Parveen, N.
name: Patton, S. J.
name: Penning, B.
name: Pereira, G.
name: Perry, E.
name: Pershing, T.
name: Piepke, A.
name: Qie, Y.
name: Reichenbacher, J.
name: Rhyne, C. A.
name: Riffard, Q.
name: Rischbieter, G. R. C.
name: Ritchey, E.
name: Riyat, H. S.
name: Rosero, R.
name: Rushton, T.
name: Rynders, D.
name: Santone, D.
name: Sazzad, A. B. M. R.
name: Schnee, R. W.
name: Sehr, G.
name: Shafer, B.
name: Shaw, S.
name: Shutt, T.
name: Silk, J. J.
name: Silva, C.
name: Sinev, G.
name: Siniscalco, J.
name: Smith, R.
name: Solovov, V. N.
name: Sorensen, P.
name: Soria, J.
name: Stevens, A.
name: Stifter, K.
name: Suerfu, B.
name: Sumner, T. J.
name: Szydagis, M.
name: Tiedt, D. R.
name: Timalsina, M.
name: Tong, Z.
name: Tovey, D. R.
name: Tranter, J.
name: Trask, M.
name: Tripathi, M.
name: Vacheret, A.
name: Vaitkus, A. C.
name: Valentino, O.
name: Velan, V.
name: Wang, A.
name: Wang, J. J.
name: Wang, Y.
name: Watson, J. R.
name: Weeldreyer, L.
name: Whitis, T. J.
name: Wild, K.
name: Williams, M.
name: Wisniewski, W. J.
name: Wolf, L.
name: Wolfs, F. L. H.
name: Woodford, S.
name: Woodward, D.
name: Wright, C. J.
name: Xia, Q.
name: Xu, J.
name: Xu, Y.
name: Yeh, M.
name: Yeum, D.
name: Zha, W.
name: Zweig, E. A.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The broad physics reach of the LUX-ZEPLIN (LZ) experiment covers rare phenomena beyond the direct detection of dark matter. We report precise measurements of the extremely rare decay of $^{124}$Xe through the process of two-neutrino double electron capture (2$ν$2EC), utilizing a $1.39\,\mathrm{kg} \times \mathrm{yr}$ isotopic exposure from the first LZ science run. A half-life of $T_{1/2}^{2\nu2\mathrm{EC}} = (1.09 \pm 0.14_{\text{stat}} \pm 0.05_{\text{sys}}) \times 10^{22}\,\mathrm{yr}$ is observed with a statistical significance of $8.3\,σ$, in agreement with literature. First empirical measurements of the KK capture fraction relative to other K-shell modes were conducted, and demonstrate consistency with respect to recent signal models at the $1.4\,σ$ level.
description: 15 pages, 3 figures