Constraints on Ultralight Scalar Dark Matter with Quadratic Couplings

Understand

Ultralight dark matter is a compelling dark matter candidate.

• In this work, we examine the impact of quadratically-coupled ultralight dark matter on the predictions of Big Bang Nucleosynthesis.
• The presence of ultralight dark matter can modify the effective values of fundamental constants during Big Bang Nucleosynthesis, modifying the predicted abundances of the primordial elements such as Helium-4.
• We improve upon the existing literature in two ways: firstly, we take into account the thermal mass acquired by the ultralight dark matter due to its quadratic interactions with the Standard Model bath, which affects the cosmological evolution of the dark matter.