Cosmological constraints on dark scalar

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.

Automated summary

This study discusses the cosmological constraints on a dark scalar particle mixing with the Standard Model Higgs boson. The production process of the dark scalar when the reheating temperature of the Universe is very low is given special attention, allowing for a conservative limit on the low-mass scalar particle. The effect of the self-interaction of the dark scalars on cosmological constraints is also investigated.