Search for double-beta decay of 136 Xe to excited states of 136 Ba with the KamLAND-Zen experiment


Journal Article

© 2015 Elsevier B.V. A search for double-beta decays of 136Xe to excited states of 136Ba has been performed with the first phase data set of the KamLAND-Zen experiment. The 01+, 21+ and 22+ transitions of 0νββ decay were evaluated in an exposure of 89.5 kg⋅yr of 136Xe, while the same transitions of 2νββ decay were evaluated in an exposure of 61.8 kg⋅yr. No excess over background was found for all decay modes. The lower half-life limits of the 21+ state transitions of 0νββ and 2νββ decay were improved to T1/20ν(0+→21+)>2.6×1025 yr and T1/22ν(0+→21+)>4.6×1023 yr (90% C.L.), respectively. We report on the first experimental lower half-life limits for the transitions to the 01+ state of 136Xe for 0νββ and 2νββ decay. They are T1/20ν(0+→01+)>2.4×1025 yr and T1/22ν(0+→01+)>8.3×1023 yr (90% C.L.). The transitions to the 22+ states are also evaluated for the first time to be T1/20ν(0+→22+)>2.6×1025 yr and T1/22ν(0+→22+)>9.0×1023 yr (90% C.L.). These results are compared to recent theoretical predictions.

Full Text

Duke Authors

Cited Authors

  • Asakura, K; Gando, A; Gando, Y; Hachiya, T; Hayashida, S; Ikeda, H; Inoue, K; Ishidoshiro, K; Ishikawa, T; Ishio, S; Koga, M; Matsuda, S; Mitsui, T; Motoki, D; Nakamura, K; Obara, S; Otani, M; Oura, T; Shimizu, I; Shirahata, Y; Shirai, J; Suzuki, A; Tachibana, H; Tamae, K; Ueshima, K; Watanabe, H; Xu, BD; Yoshida, H; Kozlov, A; Takemoto, Y; Yoshida, S; Fushimi, K; Banks, TI; Berger, BE; Fujikawa, BK; O'Donnell, T; Winslow, LA; Efremenko, Y; Karwowski, HJ; Markoff, DM; Tornow, W; Detwiler, JA; Enomoto, S; Decowski, MP

Published Date

  • February 1, 2016

Published In

Volume / Issue

  • 946 /

Start / End Page

  • 171 - 181

International Standard Serial Number (ISSN)

  • 0375-9474

Digital Object Identifier (DOI)

  • 10.1016/j.nuclphysa.2015.11.011

Citation Source

  • Scopus