Signal strength and W-boson mass measurements as a probe of the electro-weak phase transition at colliders -- Snowmass White Paper

TL;DR

This white paper explores how measurements of the Higgs boson and W-boson mass at colliders can test for a strong first-order electroweak phase transition in an extended scalar sector model, relevant for baryogenesis.

Contribution

It identifies parameter regions in a singlet-extended Standard Model that enable a strong electroweak phase transition and discusses how collider measurements can probe these regions.

Findings

Parameter space allows for strong first-order phase transition.

Higgs signal strength measurements can test the model.

W-boson mass precision can provide additional constraints.

Abstract

We consider an extension of the scalar sector of the Standard Model (SM) by an additional gauge singlet, which mixes with a part of the SM-like Higgs doublet. Within this model, parameter-space regions exist that can lead to a strong first-order electro-weak phase transition, a necessary condition for electro-weak baryogenesis. We discuss how such regions of the parameter space can be tested using the SM-like Higgs boson's signal strength measurements, as well as precision observables, such as e.g. the W-boson mass, at current and future colliders.