We report on preliminary results from the second phase of KamLAND-Zen double beta decay search experiment based on 114.8 days with 383 kg of 136Xe. Second phase of KamLAND-Zen was started after the purification to reduce the dominant 110mAg background identified by first phase data. The background was reduced by more than a factor of 10 by purification for liquid scintillator and xenon gas. By combining the first and second phase data and applying the improved event selection, we obtained a preliminary lower limit for the neutrinoless double-beta decay half-life, T1/2 0ν>2.6×1025 yr at 90% C.L. We also present the prospects about current phase of KamLAND-Zen and next phases with upgrades.
ASJC Scopus subject areas
- Nuclear and High Energy Physics