Reheating the Standard Model from a hidden sector

TL;DR

This paper explores a cosmological scenario where a hidden sector, initially decoupled, later heats the Standard Model through a tiny portal, affecting dark matter abundance and nucleosynthesis.

Contribution

It introduces a viable reheating mechanism via a hidden sector with a small portal coupling, addressing dark matter and nucleosynthesis constraints.

Findings

The scenario can produce the correct dark matter abundance.

Big Bang Nucleosynthesis remains successful under this model.

Isocurvature perturbations from a primordial Higgs condensate are not problematic.

Abstract

We consider a scenario where the inflaton decays to a hidden sector thermally decoupled from the visible Standard Model sector. A tiny portal coupling between the hidden and the visible sectors later heats the visible sector so that the Standard Model degrees of freedom come to dominate the energy density of the Universe before Big Bang Nucleosynthesis. We find that this scenario is viable, although obtaining the correct dark matter abundance and retaining successful Big Bang Nucleosynthesis is not obvious. We also show that the isocurvature perturbations constituted by a primordial Higgs condensate are not problematic for the viability of the scenario.