KamLAND-Zen

Neutrinoless double beta (0nbb) decay requires Majorana nature of the neutrino and lepton number violation. Assuming the minimal mechanism of the decay, it would constrain the neutrino mass hierarchy and mass scale via phase space factor and nuclear matrix element. 

KamLAND-Zen searches for neutrinoless double beta decay with Xe-136 loaded liquid scintillator. Results from “KamLAND-Zen 400” are based upon data collected from 2011 to 2015 and we obtained the most stringent lower limit for 0nbb decay half-life of Xe-136, 1.07*10^26 yrs at 90% C.L. Next phase, “KamLAND-Zen 800” is in preparation and will start data taking in this year. In this talk, the current status of KamLAND-Zen will be reported.