Light color octet scalars in the minimal SO(10) grand unification

TL;DR

This paper explores how TeV-scale color octet scalars in non-supersymmetric SO(10) grand unification influence matter stability bounds, revealing a link between octet mass, unification scale, and proton lifetime.

Contribution

It demonstrates that two-loop corrections revive the scenario of light color octet scalars in SO(10) GUTs, establishing a correlation with unification scale and proton decay predictions.

Findings

Light color octet scalars can be within LHC reach.

Proton lifetime predictions are linked to octet mass and unification scale.

Two-loop corrections are crucial for viability of the scenario.

Abstract

We analyze the relation between the present (and foreseen) bounds on matter stability and the presence of TeV-scale color octet scalar states in nonsupersymmetric SO(10) grand unification with one adjoint Higgs representation triggering the symmetry breaking. This scenario, discarded long ago due to tree-level tachyonic instabilities appearing in all phenomenologically viable breaking patterns, has been recently revived at the quantum level. By including the relevant two-loop corrections we find a tight correlation between the octet mass and the unification scale which either requires a light color octet scalar within the reach of the LHC or, alternatively, a proton lifetime accessible to the forthcoming megaton-scale facilities.