Primordial Black Hole Formation and Multimessenger Signals in a Complex Singlet Extension of the Standard Model

TL;DR

This paper explores how a complex singlet extension of the Standard Model can lead to primordial black hole formation during a first-order electroweak phase transition, with observable signals in gravitational waves and collider experiments.

Contribution

It provides a detailed analysis linking primordial black hole production, gravitational wave signals, and collider signatures within a realistic extended Standard Model framework.

Findings

Parameter regions consistent with microlensing constraints identified

Predicted stochastic gravitational waves detectable by future space-based detectors

Deviations in Higgs triple coupling measurable at future lepton colliders

Abstract

We investigate the formation of primordial black holes (PBHs) induced by a first-order electroweak phase transition in a realistic renormalizable framework, the complex singlet extension of the Standard Model. We perform a quantitative analysis of the PBH abundance and identify parameter regions consistent with current microlensing constraints. Furthermore, we show that the same parameter space predicts observable stochastic gravitational waves within the sensitivities of future space-based detectors, as well as a sizable deviation in the Higgs triple coupling that can be probed at future lepton colliders. Our results highlight a comprehensive multimessenger framework in which PBH, gravitational wave, and collider observations can jointly test the dynamics of a strongly first-order electroweak phase transition in the early Universe.