Heavy neutrino mass scale and quark-lepton symmetry

Abstract

Assuming hierarchical neutrino masses we calculate the heavy neutrino mass scale in the seesaw mechanism from experimental data on oscillations of solar and atmospheric neutrinos and quark-lepton symmetry. The resulting scale is around or above the unification scale, unless the two lightest neutrinos have masses of opposite sign, in which case the resulting scale can be intermediate.

Comments: 7 pages RevTex, without figures. Corrected version with more comments