KamLAND-Zen

KamLAND-Zen searches for neutrinoless double beta (0nbb) 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 136Xe, 1.07*10^26 yrs at 90% C.L. Next phase, "KamLAND-Zen800" is in preparation and will start data taking in this year. We will report the current status. Future prospects of the experiment, "KamLAND2-Zen" is also presented

Combined Pre-Supernova Alert System with Kamland and Super-Kamiokande

International audiencePreceding a core-collapse supernova, various processes produce an increasing amount of neutrinos of all flavors characterized by mounting energies from the interior of massive stars. Among them, the electron antineutrinos are potentially detectable by terrestrial neutrino experiments such as KamLAND and Super-Kamiokande via inverse beta decay interactions. Once these pre-supernova neutrinos are observed, an early warning of the upcoming core-collapse supernova can be provided. In light of this, KamLAND and Super-Kamiokande have been monitoring pre-supernova neutrinos since 2015 and 2021, respectively. Recently, we performed a joint study between KamLAND and Super-Kamiokande on pre-supernova neutrino detection. A pre-supernova alert system combining the KamLAND detector and the Super-Kamiokande detector is developed and put into operation, which can provide a supernova alert to the astrophysics community. Fully leveraging the complementary properties of these two detectors, the combined alert is expected to resolve a pre-supernova neutrino signal from a 15 M$_{\odot}$ star within 510 pc of the Earth, at a significance level corresponding to a false alarm rate of no more than 1 per century. For a Betelgeuse-like model with optimistic parameters, it can provide early warnings up to 12 hours in advance