Higgs Self-Coupling as a Probe of Electroweak Phase Transition

TL;DR

This paper discusses how deviations in the Higgs boson self-coupling can serve as indicators of a strong first-order electroweak phase transition, linking collider measurements to early universe physics.

Contribution

It establishes a correlation between electroweak phase transition dynamics and Higgs self-coupling deviations in extended Standard Model frameworks.

Findings

Models with strong first-order EWPT predict large Higgs self-coupling deviations.

Deviations of order one are typical in such models.

Future collider experiments could detect these deviations.

Abstract

We argue that, within a broad class of extensions of the Standard Model, there is a tight corellation between the dynamics of the electroweak phase transition and the cubic self-coupling of the Higgs boson: Models which exhibit a strong first-order EWPT predict a large deviation of the Higgs self-coupling from the Standard Model prediction, as long as no accidental cancellations occur. Order-one deviations are typical. This shift would be observable at the Large Hadron Collider if the proposed luminosity or energy upgrades are realized, as well as at a future electron-positron collider such as the proposed International Linear Collider. These measurements would provide a laboratory test of the dynamics of the electroweak phase transition.