Neutralino Dark Matter in an SO(10) Model with Two-step Intermediate Scale Symmetry Breaking

TL;DR

This paper explores a supersymmetric SO(10) GUT with a two-step symmetry breaking chain, analyzing its low-energy phenomenology and viability of neutralino dark matter, highlighting differences from minimal models and the impact of neutrino masses.

Contribution

It introduces a specific SO(10) GUT model with a detailed symmetry breaking chain and additional Higgs doublets, analyzing its phenomenology and dark matter implications.

Findings

Neutralino dark matter remains viable in this model.

Allowed parameter space is more constrained at small and moderate tanβ.

Results depend strongly on light neutrino masses.

Abstract

We consider a supersymmetric Grand Unified Theory (GUT) based on the gauge group SO(10) suggested by Aulakh et al., which features two--step intermediate symmetry breaking, $SO(10) \to SU(4)_C \times SU(2)_L \times SU(2)_R \to SU(3)_C \times U(1)_{B-L} \times SU(2)_L \times SU(2)_R \to SU(3)_C \times SU(2)_L \times U(1)_Y$. {\bf $45, 54, 126+\overline{126}$} dimensional representations of Higgs superfields are employed to achieve this symmetry breaking chain. We also introduce a second, very heavy, pair of Higgs doublets, which modifies the Yukawa couplings of matter fields relative to minimal SO(10) predictions. We analyze the differences in the low energy phenomenology compared to that of mSUGRA, assuming universal soft breaking scalar masses, gaugino masses and trilinear couplings at the GUT scale. We find that thermal neutralino Dark Matter remains viable in this scenario, although for small and moderate values of $\tan\beta$ the allowed region is even more highly constrained than in mSUGRA, and depends strongly on the the light neutrino masses.