Brans-Dicke Theory and primordial black holes in Early Matter-Dominated Era

TL;DR

This paper investigates how primordial black holes formed during an early matter-dominated era in Brans-Dicke gravity differ from those in radiation-dominated eras, showing faster evaporation and increased formation constraints.

Contribution

It demonstrates primordial black hole formation in a matter-dominated era within Brans-Dicke theory and compares their evolution and constraints to radiation-dominated cases.

Findings

Primordial black holes evaporate faster in matter-dominated era.

Fewer primordial black holes survive to the present in this scenario.

Formation constraints are larger, indicating enhanced formation during matter domination.

Abstract

We show that primordial black holes can be formed in the matter-dominated era with gravity described by the Brans-Dicke theory. Considering an early matter-dominated era between inflation and reheating, we found that the primordial black holes formed during that era evaporate at a quicker than those of early radiation-dominated era. Thus, in comparison with latter case, less number of primordial black holes could exist today. Again the constraints on primordial black hole formation tend towards the larger value than their radiation-dominated era counterparts indicating a significant enhancement in the formation of primordial black holes during the matter-dominaed era.