Absolute Scale of Neutrino Mass

Neutrinos are elementary particles with no electric and color charge and interact weakly with other particles. According to our current knowledge, neutrinos are the second most abundant particle after photons in the universe. Their interpretation and understanding are of great importance for Particle Physics, Astrophysics, Cosmology, and inter-related disciplines; however, the experimental study is not easy at all because of their rare interactions with matter. After long-standing efforts, observations of neutrino oscillation at SNO and Super-kamioKande have revealed that neutrinos have non-zero, tiny masses, a first discovery of physics beyond the Standard Model (SM). In this poster, I will highlight in brief the physics of massive neutrinos and the absolute scale of neutrino mass in the context of Double Beta Decay $(0 uetaeta)$, a rare process violating the lepton number conservation of SM. Their connection to Dirac and Majorana nature is going be tested at the LEGEND Experiment in the near future and current sensitivities of LEGEND-200 in the inverted mass hierarchy region will be discussed in this poster.