Testing Electroweak Baryogenesis with Future Colliders

TL;DR

This paper explores how future colliders, especially a 100 TeV hadron collider, can test electroweak baryogenesis models, including challenging scenarios that are hard to detect experimentally.

Contribution

It proposes a framework for testing EWBG at future colliders and introduces a 'nightmare scenario' that challenges experimental detection, assessing collider capabilities.

Findings

A 100 TeV collider can test most EWBG scenarios.

Certain models remain difficult to test even with future colliders.

A factorized approach helps distinguish phase transition sources from CP violation.

Abstract

Electroweak Baryogenesis (EWBG) is a compelling scenario for explaining the matter-antimatter asymmetry in the universe. Its connection to the electroweak phase transition makes it inherently testable. However, completely excluding this scenario can seem difficult in practice, due to the sheer number of proposed models. We investigate the possibility of postulating a "no-lose" theorem for testing EWBG in future e+e- or hadron colliders. As a first step we focus on a factorized picture of EWBG which separates the sources of a stronger phase transition from those that provide new sources of CP violation. We then construct a "nightmare scenario" that generates a strong first-order phase transition as required by EWBG, but is very difficult to test experimentally. We show that a 100 TeV hadron collider is both necessary and possibly sufficient for testing the parameter space of the nightmare scenario that is consistent with EWBG.