Neutrinoless Double Beta Decay (0νββ) is a hypothetical lepton-number-violating process and its existence is one of the most important questions in particle physics. The discovery of 0νββ would answer persistent questions related to the intrinsic nature of neutrino mass and provide a window into physics beyond the Standard Model. KamLAND-Zen is one of the world-leading efforts in the search of 0νββ. Data was recently collected with 735 kg of Xe-136 and analyzed using a frequentist likelihood analysis to set a limit on the 0νββ half-life. In addition to the well-established frequentist approach, I conduct a Bayesian analysis with a Markov Chain Monte Carlo (MCMC). The Bayesian approach allows the use modern statistical tools and serves as an important cross check of the frequentist analysis. A good agreement has been reached between the frequentist and Bayesian analysis on individual background level.
This poster reports the newest 0νββ limit from Bayesian analysis using KamLAND-Zen 800 data.