Abstract
We study a renormalizable SUSY SO(10) GUT model where the Yukawa couplings of single 10, single $${\bf \overline{126}}$$ and single 120 fields, Y10, Y126, Y120, account for the quark and lepton Yukawa couplings and the neutrino mass. We pursue the possibility that Y10, Y126, Y120 reproduce the correct quark and lepton masses, CKM and PMNS matrices and neutrino mass differences, and at the same time suppress dimension-5 proton decays (proton decays via colored Higgsino exchange) through their texture, so that the soft SUSY breaking scale can be reduced as much as possible without conflicting the current experimental bound on proton decays. We perform a numerical search for such a texture, and investigate implications of that texture on unknown neutrino parameters, the Dirac CP phase of PMNS matrix, the lightest neutrino mass and the (1, 1)-component of the neutrino mass matrix in the charged lepton basis. Here we concentrate on the case when the active neutrino mass is generated mostly by the Type-2 seesaw mechanism, in which case we can obtain predictions for the neutrino parameters from the condition that dimension-5 proton decays be suppressed as much as possible.