Bounds on velocity-dependent dark matter-proton scattering from Milky Way satellite abundance

Kavli Affiliate: Risa H. Wechsler

| First 5 Authors: Karime Maamari, Vera Gluscevic, Kimberly K. Boddy, Ethan O. Nadler, Risa H. Wechsler

| Summary:

We use the latest measurements of the Milky Way satellite population from the
Dark Energy Survey and Pan-STARRS1 to infer the most stringent astrophysical
bound to date on velocity-dependent interactions between dark matter particles
and protons. We model the momentum-transfer cross section as a power law of the
relative particle velocity $v$ with a free normalizing amplitude,
$sigma_text{MT}=sigma_0 v^n$, to broadly capture the interactions arising
within the non-relativistic effective theory of dark matter-proton scattering.
The scattering leads to a momentum and heat transfer between the baryon and
dark matter fluids in the early Universe, ultimately erasing structure on small
physical scales and reducing the abundance of low-mass halos that host dwarf
galaxies today. From the consistency of observations with the cold
collisionless dark matter paradigm, using a new method that relies on the most
robust predictions of the linear perturbation theory, we infer an upper limit
on $sigma_0$ of $1.4times10^{-23}$, $2.1times10^{-19}$, and
$1.0times10^{-12} mathrm{cm}^2$, for interaction models with $n=2,4,6$,
respectively, for a dark matter particle mass of $10 mathrm{MeV}$. These
results improve observational limits on dark matter–proton scattering by
orders of magnitude and thus provide an important guide for viable sub-GeV dark
matter candidates.

| Search Query: ArXiv Query: search_query=au:”Risa H. Wechsler”&id_list=&start=0&max_results=10

Read More