Dimensional reduction of the Standard Model coupled to a new singlet scalar field

TL;DR

This paper develops a dimensionally reduced effective theory for the Standard Model with a heavy singlet scalar, enabling efficient nonperturbative studies of the electroweak phase transition relevant for baryogenesis and gravitational wave production.

Contribution

It introduces a method to integrate out a superheavy singlet scalar, simplifying the analysis of the electroweak phase transition in extended Standard Model scenarios.

Findings

Effective theory involving only Higgs and gauge fields derived

Facilitates nonperturbative computation of phase transition properties

Enhances understanding of electroweak baryogenesis and gravitational waves

Abstract

We derive an effective dimensionally reduced theory for the Standard Model augmented by a real singlet scalar. We treat the singlet as a superheavy field and integrate it out, leaving an effective theory involving only the Higgs and $\mathrm{SU}(2)_\mathrm{L} \times \mathrm{U}(1)_Y$ gauge fields, identical to the one studied previously for the Standard Model. This opens up the possibility of efficiently computing the order and strength of the electroweak phase transition, numerically and nonperturbatively, in this extension of the Standard Model. Understanding the phase diagram is crucial for models of electroweak baryogenesis and for studying the production of gravitational waves at thermal phase transitions.