Probing Unification With Precision Higgs Physics

TL;DR

This paper suggests that precise measurements of Higgs Yukawa couplings at the LHC can serve as a novel probe for grand unification theories, especially through deviations in tau Yukawa coupling.

Contribution

It introduces a new method to test grand unification by analyzing correlated patterns in Higgs Yukawa couplings at the LHC, focusing on the tau coupling deviation.

Findings

Tau Yukawa coupling deviation is the largest among third-generation couplings.

Correlated patterns in Yukawa couplings can indicate unification effects.

Future LHC measurements can potentially reveal signs of grand unification.

Abstract

We propose a novel approach of probing grand unification through precise measurements on the Higgs Yukawa couplings at the LHC. This idea is well motivated by the appearance of effective operators not suppressed by the mass scale of unification $M_{\rm{U}}$ in realistic models of unification with the minimal structure of Yukawa sector. Such operators modify the Higgs Yukawa couplings in correlated patterns at scale $M_{\rm{U}}$ that hold up to higher-order corrections. The coherences reveal a feature that, the deviation of tau Yukawa coupling relative to its standard model value at the weak scale is the largest one among the third-generation Yukawa couplings. This feature, if verified by the future LHC, can serve as a hint of unification.