Sparticle Mass Spectra from SO(10) Grand Unified Models with Yukawa Coupling Unification

TL;DR

This paper explores superparticle spectra in SO(10) GUT models with Yukawa unification, showing how non-universal scalar masses and D-term contributions can produce viable electroweak symmetry breaking and distinctive collider signatures.

Contribution

It introduces a method to generate consistent sparticle spectra in SO(10) models with high tanβ by incorporating non-universal scalar masses and D-term effects.

Findings

Viable sparticle spectra can be achieved with non-universal GUT-scale scalar masses.

Light bottom squark can be the lightest squark in SO(10) models.

Implications for collider searches, especially for bottom squark pair production.

Abstract

We examine the spectrum of superparticles obtained from the minimal SO(10) grand unified model, where it is assumed the gauge symmetry breaking yields the Minimal Supersymmetric Standard Model (MSSM) as the effective theory at $M_{GUT}\sim 2\times 10^{16}$ GeV. In this model, unification of Yukawa couplings implies a value of $\tan\beta\sim 45-55$. At such high values of $\tan\beta$, assuming universality of scalar masses, the usual mechanism of radiative electroweak symmetry breaking breaks down. We show that a set of weak scale sparticle masses consistent with radiative electroweak symmetry breaking can be generated by imposing non-universal GUT scale scalar masses consistent with universality within SO(10) plus extra $D$-term contributions associated with the reduction in rank of the gauge symmetry group when SO(10) spontaneously breaks to $SU(3)\times SU(2)\times U(1)$. We comment upon the consequences of the sparticle mass spectrum for collider searches for supersymmetry. One implication of SO(10) unification is that the light bottom squark can be by far the lightest of the squarks. This motivates a dedicated search for bottom squark pair production at $p\bar{p}$ and $e^+e^-$ colliders.