Limit on Neutrinoless {\beta}{\beta} Decay of Xe136 from the First Phase of KamLANDZen and Comparison with the Positive Claim in Ge76
Abstract
We present results from the first phase of the KamLANDZen doublebeta decay experiment, corresponding to an exposure of 89.5 kg yr of Xe136. We obtain a lower limit for the neutrinoless doublebeta decay halflife of T_{1/2}^{0{\nu}} > 1.9 x 10^{25} yr at 90% C.L. The combined results from KamLANDZen and EXO200 give T_{1/2}^{0{\nu}} > 3.4 x 10^{25} yr at 90% C.L., which corresponds to a Majorana neutrino mass limit of <m_{{\beta}{\beta}}> < (120250) meV based on a representative range of available matrix element calculations. Using those calculations, this result excludes the Majorana neutrino mass range expected from the neutrinoless doublebeta decay detection claim in Ge76, reported by a part of the HeidelbergMoscow Collaboration, at more than 97.5% C.L.
 Publication:

arXiv eprints
 Pub Date:
 November 2012
 arXiv:
 arXiv:1211.3863
 Bibcode:
 2012arXiv1211.3863K
 Keywords:

 High Energy Physics  Experiment;
 Nuclear Experiment
 EPrint:
 5 pages, 4 figures