Cosmological Constraints on Dark Scalar

TL;DR

This paper investigates cosmological limits on a dark scalar particle mixing with the Higgs, emphasizing low reheating temperatures and scalar self-interactions to establish conservative constraints.

Contribution

It provides the most conservative cosmological constraints on low-mass dark scalars, considering low reheating temperatures and scalar self-interactions, complementing other experimental bounds.

Findings

Low reheating temperatures affect dark scalar production.

Self-interactions significantly influence cosmological constraints.

Constraints are conservative and complement accelerator and astrophysical data.

Abstract

We discuss cosmological constraints on a dark scalar particle mixing with the Standard Model Higgs boson. We pay particular attention to the dark scalar production process when the reheating temperature of the Universe is very low, which allows us to give a conservative limit on the low-mass scalar particle. We also study the effect of the self-interaction of the dark scalars and find this has a significant impact on the cosmological constraints. We obtain the most conservative cosmological constraint on the dark scalar, which is complementary to accelerator experiments and astrophysical observations.