On teraelectronvolt Majorana neutrinos

The issue of existence of Majorana neutrinos with masses of the order of TeV and substantial couplings is addressed. A general neutrino mass matrix M-v with both features is constructed, however, the form of M-v is constrained very much by severe relations among the elements of m(D) and M-R sub-matrices of M-v. These general relations follow from the perturbative construction of the light neutrino mass spectrum. To avoid such large correlations between low mass parameters in m(D) and large mass parameters in M-R, the Jezabek-Sumino see-saw model of bi-maximal neutrino mixing adopted to the TeV scale and the issue of possible symmetries of the matrix M-v are discussed. Results are supported by a few numerical examples which show directly the complexity of the problem.