Non-thermal Origin of Asymmetric Dark Matter from Inflaton and Primordial Black Holes

TL;DR

This paper explores how asymmetric dark matter and baryon asymmetry can originate from non-thermal decay of right-handed neutrinos, produced either by inflaton decay or primordial black hole evaporation, and constrains the model parameters accordingly.

Contribution

It introduces a novel framework linking non-thermal RHN production from inflaton decay and primordial black holes to asymmetric dark matter and baryogenesis, with detailed cosmological constraints.

Findings

Non-thermal RHN decay can generate correct dark matter and baryon asymmetry.

Primordial black holes enhance baryon and dark matter abundance compared to thermal scenarios.

The model's parameter space is constrained by cosmological bounds and observational prospects.

Abstract

We study the possibility of cogenesis of baryon and dark matter (DM) from the out-of-equilibrium CP violating decay of right handed neutrino (RHN) that are dominantly of non-thermal origin. While the RHN and its heavier partners can take part in light neutrino mass generation via Type-I seesaw mechanism, the decay of RHN into dark and visible sectors can create respective asymmetries simultaneously. The non-thermal sources of RHN considered are {\bf (a)} on-shell decay of inflaton, and {\bf (b)} evaporation of ultralight primordial black holes (PBH). After setting up the complete set of Boltzmann equations in both these scenarios, we constrain the resulting parameter space of the particle physics setup, along with inflaton and PBH sectors from the requirement of generating correct (asymmetric) DM abundance and baryon asymmetry, while being in agreement with other relevant cosmological bounds. Scenario {\bf (a)} links the common origin of DM and baryon asymmetry to post-inflationary reheating via RHNs produced in inflaton decay, whereas in scenario {\bf (b)} we find enhancement of baryon and DM abundance, compared to the purely thermal scenarios, in presence of PBH with appropriate mass and initial fraction. Although the minimal setup itself is very predictive with observational consequences, details of the UV completion of the dark sector can offer several complementary probes.