Updated BBN Constraints on Ultralight Scalar Dark Matter
This event is part of the HET Seminar Series.
Ultralight scalars are an attractive dark matter candidate.
We consider the effect of such a dark matter candidate on predictions of Big Bang Nucleosynthesis. As a first study, we look at an ultralight scalar with universal couplings to all massive Standard Model particles. One striking consequence of this new coupling is a change in the predicted abundances of the light elements. In this talk, I will present updated constraints on ultralight scalar dark matter from Helium-4, taking into account the effect of the back-reaction of the Standard Model particles on the dark sector. This effect was neglected in previous works but has noticeable effects. Furthermore, I will present previously uncalculated constraints from deuterium, as well as a comparison to other probes for ultralight scalar dark matter.