MOON for symmetry studies of neutrinos by double beta decays and neutrino nuclear responses

Neutrino-less double beta decays (image) are used for high sensitivity studies of symmetry properties of neutrinos such as the Majorana nature of neutrinos, the absolute mass scale, the CP at the lepton sector, and others. Neutrino nuclear responses (image nuclear matrix elements) are crucial for extracting these neutrino properties from image experiments. This is a brief report of the present status of MOON (spectroscopic image experiment) with the ν-mass sensitivity of 100-30 meV, and experimental ways to study the neutrino nuclear responses.