Limits on Majoron-emitting double-β decays of 136Xe in the KamLAND-Zen experiment


Journal Article

We present limits on Majoron-emitting neutrinoless double-β decay modes based on an exposure of 112.3 days with 125 kg of 136Xe. In particular, a lower limit on the ordinary (spectral index n=1) Majoron-emitting decay half-life of 136Xe is obtained as T1/20νχ0>2.6×1024 yr at 90% C.L., a factor of five more stringent than previous limits. The corresponding upper limit on the effective Majoron-neutrino coupling, using a range of available nuclear matrix calculations, is gee<(0.8-1.6) ×10-5. This excludes a previously unconstrained region of parameter space and strongly limits the possible contribution of ordinary Majoron emission modes to 0νββ decay for neutrino masses in the inverted hierarchy scheme. © 2012 American Physical Society.

Full Text

Duke Authors

Cited Authors

  • Gando, A; Gando, Y; Hanakago, H; Ikeda, H; Inoue, K; Kato, R; Koga, M; Matsuda, S; Mitsui, T; Nakada, T; Nakamura, K; Obata, A; Oki, A; Ono, Y; Shimizu, I; Shirai, J; Suzuki, A; Takemoto, Y; Tamae, K; Ueshima, K; Watanabe, H; Xu, BD; Yamada, S; Yoshida, H; Kozlov, A; Yoshida, S; Banks, TI; Detwiler, JA; Freedman, SJ; Fujikawa, BK; Han, K; O'Donnell, T; Berger, BE; Efremenko, Y; Karwowski, HJ; Markoff, DM; Tornow, W; Enomoto, S; Decowski, MP

Published Date

  • August 6, 2012

Published In

Volume / Issue

  • 86 / 2

Electronic International Standard Serial Number (EISSN)

  • 1089-490X

International Standard Serial Number (ISSN)

  • 0556-2813

Digital Object Identifier (DOI)

  • 10.1103/PhysRevC.86.021601

Citation Source

  • Scopus