Doubly peaked induced stochastic gravitational wave background : Testing baryogenesis from primordial black holes

TL;DR

This paper proposes detecting a distinctive doubly peaked gravitational wave spectrum as a test for baryogenesis facilitated by primordial black hole evaporation, offering a novel observational signature for this high-energy early universe process.

Contribution

It introduces a new method to test baryogenesis from primordial black holes via the detection of a characteristic doubly peaked gravitational wave spectrum.

Findings

Two peaks in the GW spectrum are generated at the start of radiation domination.

The GW peaks serve as a smoking gun for non-thermal baryogenesis.

The spectral shape is unique and detectable with future GW observatories.

Abstract

Hawking evaporation of primordial black holes (PBHs) can facilitate the generation of matter-antimatter asymmetry. We focus on ultra-low mass PBHs that briefly dominate the universe and evaporate before the big bang nucleosynthesis. We propose a novel test of this scenario by detecting its characteristic doubly peaked gravitational wave (GW) spectrum in future GW observatories. Here the first order adiabatic perturbation from inflation and from the isocurvature perturbations due to PBH distribution, source tensor perturbations in second-order and lead to two peaks in the induced GW background. These resonant peaks are generated at the beginning of standard radiation domination in the presence of a prior PBH-dominated era. This unique GW spectral shape would provide a smoking gun signal of non-thermal baryogenesis from evaporating PBHs, which is otherwise impossible to test in laboratory experiments due to the very high energy scales involved or the feeble interaction of the dark sector with the visible sector.