Cosmological Phase Transitions in Warped Space: Gravitational Waves and Collider Signatures

TL;DR

This paper investigates a 5D warped model predicting a first-order electroweak phase transition with observable gravitational waves and collider signatures, advancing understanding of baryogenesis and experimental prospects.

Contribution

It introduces a novel superpotential formalism enabling exploration of previously inaccessible parameter regions in warped models, linking phase transitions to observable signals.

Findings

Holographic phase transition occurs at large N (~25).

Model predicts detectable stochastic gravitational wave background.

Radion may be observable in future collider experiments.

Abstract

We study the electroweak phase transition within a 5D warped model including a scalar potential with an exponential behavior, and strong back-reaction over the metric, in the infrared. By means of a novel treatment of the superpotential formalism, we explore parameter regions that were previously inaccessible. We find that for large enough values of the t'Hooft parameter (e.g. $N\simeq 25$) the holographic phase transition occurs, and it can force the Higgs to undergo a first order electroweak phase transition, suitable for electroweak baryogenesis. The model exhibits gravitational waves and colliders signatures. It typically predicts a stochastic gravitational wave background observable both at the Laser Interferometer Space Antenna and at the Einstein Telescope. Moreover the radion tends to be heavy enough such that it evades current constraints, but may show up in future LHC runs.