1. Search for Majorana Neutrinos with the Complete KamLAND-Zen Dataset
- Author
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Abe, S., Araki, T., Chiba, K., Eda, T., Eizuka, M., Funahashi, Y., Furuto, A., Gando, A., Gando, Y., Goto, S., Hachiya, T., Hata, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Koga, M., Marthe, A., Matsumoto, Y., Mitsui, T., Miyake, H., Morita, D., Nakajima, R., Nakamura, K., Nakamura, R., Nakane, J., Ono, T., Ozaki, H., Saito, K., Sakai, T., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Tachibana, K., Tamae, K., Watanabe, H., Watanabe, K., Yoshida, S., Umehara, S., Fushimi, K., Kotera, K., Urano, Y., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Fu, Z., Ghosh, S., Smolsky, J., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Dell'Oro, S., O'Donnell, T., Detwiler, J. A., Enomoto, S., Decowski, M. P., Weerman, K. M., Grant, C., Penek, O., Song, H., Li, A., Axani, S. N., Garcia, M., and Sarfraz, M.
- Subjects
High Energy Physics - Experiment - Abstract
We present a search for neutrinoless double-beta ($0\nu\beta\beta$) decay of $^{136}$Xe using the full KamLAND-Zen 800 dataset with 745 kg of enriched xenon, corresponding to an exposure of $2.097$ ton yr of $^{136}$Xe. This updated search benefits from a more than twofold increase in exposure, recovery of photo-sensor gain, and reduced background from muon-induced spallation of xenon. Combining with the search in the previous KamLAND-Zen phase, we obtain a lower limit for the $0\nu\beta\beta$ decay half-life of $T_{1/2}^{0\nu} > 3.8 \times 10^{26}$ yr at 90% C.L., a factor of 1.7 improvement over the previous limit. The corresponding upper limits on the effective Majorana neutrino mass are in the range 28-122 meV using phenomenological nuclear matrix element calculations., Comment: arXiv admin note: text overlap with arXiv:2203.02139
- Published
- 2024