Observed neutrino flavor oscillation manifests, neutrino possess non-zero mass, this leads to the first indication of physics beyond standard model. LEGEND experiment uses 200 kg of 76Ge for the search of rare nuclear transition, 76Ge → 76Se + e− + e−, a neutrinoless double beta decay process and this would establish the Majorana nature of neutrino and determination of absolute neutrino mass.

Neutrino are the most abundant matter particle in the universe. The three active neutrino flavors (νe, νμ, ντ) are weakly interacting neutral fermions. The nature of neutrino, Dirac (ν ≠ ν) or Majorana (ν = ν) are still not clear. Search for neutrinoless double beta decay (0νββ) would then establish that neutrinos are Majorana in nature. 0νββ is a second order weak process in which, two neutrons simultaneously transform into two protons with the emission of two electrons in the final state as,(A, Z ) → (A, Z + 2) + e− + e−. This violates lepton number conservation by 2 units. Mass of the Majorana neutrino (m ) can be determined by measuring T 0ν .