Critical assessment of CMB limits on dark matter-baryon scattering: New treatment of the relative bulk velocity

Kimberly K. Boddy, Vera Gluscevic, Vivian Poulin, Ely D. Kovetz, Marc Kamionkowski, Rennan Barkana

Research output: Contribution to journalArticlepeer-review

57 Scopus citations

Abstract

We perform an improved cosmic microwave background (CMB) analysis to search for dark matter-proton scattering with a momentum-transfer cross section of the form σ0vn for n=-2 and n=-4. In particular, we present a new and robust prescription for incorporating the relative bulk velocity between the dark matter and baryon fluids into the standard linear Boltzmann calculation. Using an iterative procedure, we self-consistently include the effects of the bulk velocities in a cosmology in which dark matter interacts with baryons. With this prescription, we derive CMB bounds on the cross section, excluding σ0>2.3×10-33 cm2 for n=-2 and σ0>1.7×10-41 cm2 for n=-4 at 95% confidence, for dark matter masses below 10 MeV. Furthermore, we investigate how these constraints change when only a subcomponent of dark matter is interacting. We show that Planck limits vanish if 0.4% of dark matter is tightly coupled to baryons. We discuss the implications of our results for present and future cosmological observations.

Original languageEnglish
Article number123506
JournalPhysical Review D
Volume98
Issue number12
DOIs
StatePublished - 15 Dec 2018
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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