Renormalizable $SO(10)$ GUT with Suppressed Dimension-5 Proton Decays

TL;DR

This paper develops a renormalizable SUSY $SO(10)$ GUT model that fits fermion masses and mixings while suppressing proton decay via texture tuning, especially emphasizing the Type-2 seesaw mechanism.

Contribution

It introduces a specific Yukawa coupling texture in a SUSY $SO(10)$ GUT that simultaneously explains fermion data and suppresses dangerous proton decays, enabling lower SUSY breaking scales.

Findings

Successfully identifies textures that suppress dimension-5 proton decays.

Provides predictions for neutrino parameters and CP phases.

Highlights the correlation between proton decay suppression and neutrino mass features.

Abstract

We study a renormalizable SUSY $SO(10)$ GUT model where the Yukawa couplings of single ${\bf 10}$, single ${\bf \overline{126}}$ and single ${\bf 120}$ fields, $Y_{10},Y_{126},Y_{120}$, account for the quark and lepton Yukawa couplings and the neutrino mass. We pursue the possibility that $Y_{10},Y_{126},Y_{120}$ 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 the correlation between the suppression of dimension-5 proton decays and the neutrino parameters is expected to be most direct.