@article{3fc6a0a3f031437f9deb07e5ad28dd7c,
title = "Search for double-beta decay of 136Xe to excited states of 136Ba with the KamLAND-Zen experiment",
abstract = "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.",
keywords = "Double-beta decay, Excited state, Xe",
author = "K. Asakura and A. Gando and Y. Gando and T. Hachiya and S. Hayashida and H. Ikeda and K. Inoue and K. Ishidoshiro and T. Ishikawa and S. Ishio and M. Koga and S. Matsuda and T. Mitsui and D. Motoki and K. Nakamura and S. Obara and M. Otani and T. Oura and I. Shimizu and Y. Shirahata and J. Shirai and A. Suzuki and H. Tachibana and K. Tamae and K. Ueshima and H. Watanabe and Xu, {B. D.} and H. Yoshida and A. Kozlov and Y. Takemoto and S. Yoshida and K. Fushimi and Banks, {T. I.} and Berger, {B. E.} and Fujikawa, {B. K.} and T. O'Donnell and Winslow, {L. A.} and Y. Efremenko and Karwowski, {H. J.} and Markoff, {D. M.} and W. Tornow and Detwiler, {J. A.} and S. Enomoto and Decowski, {M. P.}",
note = "Funding Information: The KamLAND-Zen experiment is supported by JSPS KAKENHI Grant Numbers 21000001 and 26104002 ; Stichting FOM in the Netherlands; and under the U.S. Department of Energy (DOE) Grant No. DE-AC02-05CH11231 , as well as other DOE and NSF grants to individual institutions. The Kamioka Mining and Smelting Company has provided service for activities in the mine. We acknowledge the support of NII for SINET4. Publisher Copyright: {\textcopyright} 2015 Elsevier B.V.",
year = "2016",
month = feb,
day = "1",
doi = "10.1016/j.nuclphysa.2015.11.011",
language = "English",
volume = "946",
pages = "171--181",
journal = "Nuclear Physics A",
issn = "0375-9474",
publisher = "Elsevier",
}