Low-energy formulas for neutrino masses with atanβ-dependent hierarchy

Abstract
Using radiative corrections and the seesaw mechanism, we derive analytic formulas for neutrino masses at low energies in SUSY unified theories exhibiting, for the first time, a tanβ dependence of mass ratios. The enhancements of the hierarchial ratios are found to be quite significant for smaller values of tanβ. Renormalization coefficients and mass predictions are evaluated, with uncertainties, in SUSY SO(10) models having a grand desert and intermediate breaking.