| Literature DB >> 27588852 |
A Gando1, Y Gando1, T Hachiya1, A Hayashi1, S Hayashida1, H Ikeda1, K Inoue1,2, K Ishidoshiro1, Y Karino1, M Koga1,2, S Matsuda1, T Mitsui1, K Nakamura1,2, S Obara1, T Oura1, H Ozaki1, I Shimizu1, Y Shirahata1, J Shirai1, A Suzuki1, T Takai1, K Tamae1, Y Teraoka1, K Ueshima1, H Watanabe1, A Kozlov2, Y Takemoto2, S Yoshida3, K Fushimi4, T I Banks5, B E Berger2,5, B K Fujikawa2,5, T O'Donnell5, L A Winslow6, Y Efremenko2,7, H J Karwowski8, D M Markoff8, W Tornow2,8, J A Detwiler2,9, S Enomoto2,9, M P Decowski2,10.
Abstract
We present an improved search for neutrinoless double-beta (0νββ) decay of ^{136}Xe in the KamLAND-Zen experiment. Owing to purification of the xenon-loaded liquid scintillator, we achieved a significant reduction of the ^{110m}Ag contaminant identified in previous searches. Combining the results from the first and second phase, we obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>1.07×10^{26} yr at 90% C.L., an almost sixfold improvement over previous limits. Using commonly adopted nuclear matrix element calculations, the corresponding upper limits on the effective Majorana neutrino mass are in the range 61-165 meV. For the most optimistic nuclear matrix elements, this limit reaches the bottom of the quasidegenerate neutrino mass region.Entities:
Year: 2016 PMID： 27588852 DOI： 10.1103/PhysRevLett.117.082503
Source DB: PubMed Journal: Phys Rev Lett ISSN： 0031-9007 Impact factor: 9.161