Phase structure and Higgs boson mass in a Higgs-Yukawa model with a dimension-6 operator

TL;DR

This paper explores how adding a dimension-6 operator to a lattice Higgs-Yukawa model affects its phase structure and the lower Higgs boson mass bound, combining perturbative and non-perturbative methods.

Contribution

It provides a detailed analysis of the phase diagram and Higgs mass implications in a Higgs-Yukawa model with a $ ext{dim-6}$ operator, a novel extension relevant for BSM physics.

Findings

Complex phase structure with first and second order transitions.

The $ ext{dim-6}$ operator influences the Higgs mass bounds.

Non-perturbative effects are crucial for understanding the model.

Abstract

We investigate the impact of a $\lambda_6 \varphi^6$ term included in a chirally invariant lattice Higgs-Yukawa model. Such a term could emerge from BSM physics at some larger energy scale. We map out the phase structure of the Higgs-Yukawa model with positive $\lambda_6$ and negative quartic self coupling of the scalar fields. To this end, we evaluate the constraint effective potential in lattice perturbation theory and also determine the magnetization of the model via numerical simulations which allow us to reach also non-perturbative values of the couplings. As a result, we find a complex phase structure with first and second order phase transitions identified through the magnetization. Further we analyze the effect of such a $\varphi^6$ term on the lower Higgs boson mass bound to see, whether the standard model lower mass bound can be altered.