Neutrinoless double beta decays tell nature of right-handed neutrinos

Abstract

We consider the minimal seesaw model, the Standard Model extended by two right-handed neutrinos, for explaining the neutrino masses and mixing angles measured in oscillation experiments. When one of right-handed neutrinos is lighter than the electroweak scale, it can give a sizable contribution to neutrinoless double beta (0νββ) decay. We show that the detection of the 0νββ decay by future experiments gives a significant implication to the search for such a light right-handed neutrino.