Gravitational wave signatures of cogenesis from a burdened PBH

TL;DR

This paper investigates how primordial black hole evaporation, beyond semi-classical approximations, can simultaneously explain dark matter and matter-antimatter asymmetry, with implications for gravitational wave signals and cosmological constraints.

Contribution

It introduces a novel analysis of PBH evaporation effects on dark matter, baryogenesis, and gravitational waves, considering non-semiclassical modifications and memory burden impacts.

Findings

Correct DM abundance possible for PBHs > 10^3 g

Baryon asymmetry achievable with PBHs < 10^3 g

Induced gravitational waves can test memory-burden effects

Abstract

We explore the possibility of explaining the observed dark matter (DM) relic abundance, along with matter-antimatter asymmetry, entirely from the evaporation of primordial black holes (PBH) beyond the semi-classical approximation. We find that, depending on the timing of modification to the semi-classical approximation and the efficiency of the backreaction, it is possible to produce the correct DM abundance for PBHs with masses $\gtrsim\mathcal{O}(10^3)$ g, whereas producing the right amount of baryon asymmetry requires light PBHs with masses $\lesssim\mathcal{O}(10^3)$ g, satisfying bounds on the PBH mass from the Cosmic Microwave Background and Big Bang Nucleosynthesis. However, in a simplistic scenario, achieving both {\it simultaneously} is not feasible, typically because of the stringent Lyman-$\alpha$ constraint on warm dark matter mass. In addition to DM and baryon asymmetry, we also investigate the impact of memory burden on dark radiation, evaporated from PBH, constrained by the effective number of relativistic degrees of freedom $\Delta N_{\rm eff}$. Furthermore, we demonstrate how induced gravitational waves from PBH density fluctuations can provide a window to test the memory-burden effects, thereby placing constraints on either the DM mass scale or the scale of leptogenesis.