The Dark Side of the Electroweak Phase Transition

TL;DR

This paper investigates how a light GeV-scale scalar can induce a first-order electroweak phase transition, potentially enabling electroweak baryogenesis and linking cosmological phenomena with recent cosmic ray excesses, while also exploring gravitational wave signals.

Contribution

It demonstrates that a light scalar can facilitate a first-order electroweak phase transition compatible with experimental bounds within a supersymmetric model.

Findings

Light scalar induces first-order phase transition

Possible explanation for cosmic ray excesses

Detectable gravitational wave signals from transition

Abstract

Recent data from cosmic ray experiments may be explained by a new GeV scale of physics. In addition the fine-tuning of supersymmetric models may be alleviated by new O(GeV) states into which the Higgs boson could decay. The presence of these new, light states can affect early universe cosmology. We explore the consequences of a light (~ GeV) scalar on the electroweak phase transition. We find that trilinear interactions between the light state and the Higgs can allow a first order electroweak phase transition and a Higgs mass consistent with experimental bounds, which may allow electroweak baryogenesis to explain the cosmological baryon asymmetry. We show, within the context of a specific supersymmetric model, how the physics responsible for the first order phase transition may also be responsible for the recent cosmic ray excesses of PAMELA, FERMI etc. We consider the production of gravity waves from this transition and the possible detectability at LISA and BBO.