skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Search for Majorana Neutrinos Near the Inverted Mass Hierarchy Region with KamLAND-Zen

Abstract

Here, we present an improved search for neutrinoless double-beta (0νββ) decay of Xe 136 in the KamLAND-Zen experiment. Owing to purification of the xenon-loaded liquid scintillator, we achieved a significant reduction of the Ag 110m 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$$0v\atop{1/2}$$ > 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. Finally, for the most optimistic nuclear matrix elements, this limit reaches the bottom of the quasidegenerate neutrino mass region.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
1379566
Grant/Contract Number:
AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 117; Journal Issue: 8; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Gando, A., Gando, Y., Hachiya, T., Hayashi, A., Hayashida, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Karino, Y., Koga, M., Matsuda, S., Mitsui, T., Nakamura, K., Obara, S., Oura, T., Ozaki, H., Shimizu, I., Shirahata, Y., Shirai, J., Suzuki, A., Takai, T., Tamae, K., Teraoka, Y., Ueshima, K., Watanabe, H., Kozlov, A., Takemoto, Y., Yoshida, S., Fushimi, K., Banks, T. I., Berger, B. E., Fujikawa, B. K., O’Donnell, T., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., and Decowski, M. P. Search for Majorana Neutrinos Near the Inverted Mass Hierarchy Region with KamLAND-Zen. United States: N. p., 2016. Web. doi:10.1103/PhysRevLett.117.082503.
Gando, A., Gando, Y., Hachiya, T., Hayashi, A., Hayashida, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Karino, Y., Koga, M., Matsuda, S., Mitsui, T., Nakamura, K., Obara, S., Oura, T., Ozaki, H., Shimizu, I., Shirahata, Y., Shirai, J., Suzuki, A., Takai, T., Tamae, K., Teraoka, Y., Ueshima, K., Watanabe, H., Kozlov, A., Takemoto, Y., Yoshida, S., Fushimi, K., Banks, T. I., Berger, B. E., Fujikawa, B. K., O’Donnell, T., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., & Decowski, M. P. Search for Majorana Neutrinos Near the Inverted Mass Hierarchy Region with KamLAND-Zen. United States. doi:10.1103/PhysRevLett.117.082503.
Gando, A., Gando, Y., Hachiya, T., Hayashi, A., Hayashida, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Karino, Y., Koga, M., Matsuda, S., Mitsui, T., Nakamura, K., Obara, S., Oura, T., Ozaki, H., Shimizu, I., Shirahata, Y., Shirai, J., Suzuki, A., Takai, T., Tamae, K., Teraoka, Y., Ueshima, K., Watanabe, H., Kozlov, A., Takemoto, Y., Yoshida, S., Fushimi, K., Banks, T. I., Berger, B. E., Fujikawa, B. K., O’Donnell, T., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., and Decowski, M. P. 2016. "Search for Majorana Neutrinos Near the Inverted Mass Hierarchy Region with KamLAND-Zen". United States. doi:10.1103/PhysRevLett.117.082503. https://www.osti.gov/servlets/purl/1379566.
@article{osti_1379566,
title = {Search for Majorana Neutrinos Near the Inverted Mass Hierarchy Region with KamLAND-Zen},
author = {Gando, A. and Gando, Y. and Hachiya, T. and Hayashi, A. and Hayashida, S. and Ikeda, H. and Inoue, K. and Ishidoshiro, K. and Karino, Y. and Koga, M. and Matsuda, S. and Mitsui, T. and Nakamura, K. and Obara, S. and Oura, T. and Ozaki, H. and Shimizu, I. and Shirahata, Y. and Shirai, J. and Suzuki, A. and Takai, T. and Tamae, K. and Teraoka, Y. and Ueshima, K. and Watanabe, H. and Kozlov, A. and Takemoto, Y. and Yoshida, S. and Fushimi, K. and Banks, T. I. and Berger, B. E. and Fujikawa, B. K. and O’Donnell, T. and Winslow, L. A. and Efremenko, Y. and Karwowski, H. J. and Markoff, D. M. and Tornow, W. and Detwiler, J. A. and Enomoto, S. and Decowski, M. P.},
abstractNote = {Here, we present an improved search for neutrinoless double-beta (0νββ) decay of Xe136 in the KamLAND-Zen experiment. Owing to purification of the xenon-loaded liquid scintillator, we achieved a significant reduction of the Ag110m 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$0v\atop{1/2}$ > 1.07×1026 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. Finally, for the most optimistic nuclear matrix elements, this limit reaches the bottom of the quasidegenerate neutrino mass region.},
doi = {10.1103/PhysRevLett.117.082503},
journal = {Physical Review Letters},
number = 8,
volume = 117,
place = {United States},
year = 2016,
month = 8
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 43works
Citation information provided by
Web of Science

Save / Share:
  • This corrects an author affiliation for the article DOI: 10.1103/PhysRevLett.117.082503.
  • The comprehensive analyses are presented in the model with the inverted mass hierarchy for neutrinos, which follows from a geometrical structure of a (1+5) dimensional space-time where two extra dimensions are compactified on the T{sup 2}/Z{sub 3} orbifold. The model gives two large lepton flavor mixings due to the S{sub 3} structure in the (1+5) dimensional space-time. It also predicts the lightest neutrino mass as m{sub 3}=(1-50)x10{sup -5} eV and the effective neutrino mass responsible for neutrinoless double beta decays as <m>{sub ee}{approx_equal}50 meV. The low energy CP violation, J{sub CP} could be 0.02. On the other hand, the observedmore » baryon asymmetry in the present universe is produced by the nonthermal leptogenesis, which works even at the reheating temperature T{sub R}=10{sup 4}-10{sup 6} GeV. The correlation between the baryon asymmetry and the low energy CP violation is examined in this model.« less
  • Cuoricino is a bolometric experiment searching for the Neutrinoless Double Beta Decay (0{nu}DBD) of 130Te. This experiment is not only self-consistent, but it is also a test for a second-generation experiment: CUORE. After a brief discussion of 0{nu}DBD scientific framework, a presentation of the Cuoricino detector, of its current results, of the CUORE experiment and of its potentialities will be discussed.
  • In the dense supernova core, self-interactions may align the flavor polarization vectors of {nu} and {nu} and induce collective flavor transformations. Different alignment Ansaetze are known to describe approximately the phenomena of synchronized or bipolar oscillations and the split of {nu} energy spectra. We discuss another phenomenon observed in some numerical experiments in inverted hierarchy, showing features akin to a low-energy split of {nu} spectra. The phenomenon appears to be approximately described by another alignment Ansatz which, in the considered scenario, reduces the (nonadiabatic) dynamics of all energy modes to only two {nu} plus two {nu} modes. The associated spectralmore » features, however, appear to be fragile when passing from single to multiangle simulations.« less