TeV Scale See-Saw Mechanisms of Neutrino Mass Generation, the Majorana Nature of the Heavy Singlet Neutrinos and $\betabeta$-Decay

A. Ibarra, E. Molinaro, S. T. Petcov

It is shown that the Majorana nature of the heavy neutrinos $N_j$ having masses in the range of $M_j\sim (100-1000)$ GeV and present in the TeV scale type I and inverse see-saw…