DEGENERATE NEUTRINOS IN LEFT-RIGHT-SYMMETRICAL THEORY

Various hints on the neutrino masses, namely, (i) the solar neutrino deficit, (ii) the atmospheric neutrino deficit, (iii) the need for the dark matter, and/or (iv) the nonzero neutrinoless double β decay collectively imply that all the three neutrinos must be nearly degenerate. This feature can be understood in the left-right symmetric theory. We present a model based on the group SU(2)L×SU(2)R×U(1)B-L×SU(2)H which can explain the required departures from degeneracy in neutrino masses and large mixing among them without assuming any of the mixing in the quark or charged lepton sector to be large, as expected in a typical SO(10) model. © 1995 The American Physical Society.