Higgs-Yukawa model with higher dimension operators via extended mean field theory

TL;DR

This study uses extended mean field theory to analyze the Higgs-Yukawa model with higher dimension operators, revealing modifications in vacuum stability, Higgs mass fine-tuning, and the nature of the finite temperature transition, with implications for electroweak baryogenesis.

Contribution

It introduces the effects of higher dimension operators in the Higgs-Yukawa model using EMFT, showing how they alter vacuum stability and phase transition properties.

Findings

Vacuum stability discussion is modified by a $6$ term.

Higgs mass is no longer fine-tuned with higher dimension operators.

The finite temperature transition can become first order with a 6 interaction at ~1.5 TeV.

Abstract

Using extended mean field theory (EMFT) on the lattice, we study properties of the Higgs-Yukawa model as an approximation of the standard model Higgs sector, and the effect of higher dimension operators. We note that the discussion of vacuum stability is completely modified in the presence of a $\phi^6$ term, and that the Higgs mass no longer appears fine tuned. We also study the finite temperature transition. Without higher dimension operators the transition is found to be second order (crossover with gauge fields) for the experimental value of the Higgs mass $M_h=125$ GeV. By taking a $\phi^6$ interaction in the Higgs potential as a proxy for a UV completion of the standard model, the transition becomes stronger and turns first order if the scale of new physics, i.e. the mass of the lightest mediator particle, is around $1.5$ TeV. This implies that electroweak baryogenesis may be viable in models which introduce new particles around that scale.