Constraints on dark matter-neutrino scattering from the Milky-Way satellites and subhalo modeling for dark acoustic oscillations

Abstract

The elastic scattering between dark matter (DM) and radiation can potentially explain small-scale observations that the cold dark matter faces as a challenge, as damping density fluctuations via dark acoustic oscillations in the early universe erases small-scale structure. We study a semi-analytical subhalo model for interacting dark matter with radiation, based on the extended Press-Schechter formalism and subhalos' tidal evolution prescription. We also test the elastic scattering between DM and neutrinos using observations of Milky-Way satellites from the Dark Energy Survey and PanSTARRS1. We conservatively impose strong constraints on the DM-neutrino scattering cross section of σ DM–ν,n ∝ En ν (n = 0,2,4) at 95% confidence level (CL), σ DM–ν,0 < 10-32 cm2 (m DM/ GeV), σ DM–ν,2 < 10-43 cm2 (m DM/ GeV)(Eν /Eν 0)2 and σ DM–ν,4 < 10-54 cm2 (m DM /GeV)(Eν /Eν 0)4, where Eν 0 is the neutrino energy and Eν 0 is the average momentum of relic cosmic neutrinos today, Eν 0 ≃ 6.1 K. By imposing a satellite forming condition, we obtain the strongest upper bounds on the DM-neutrino cross section at 95% CL, σ DM–ν,0 < 4 × 10-34 cm2 (m DM/ GeV), σ DM–ν,2 < 10-46 cm2 (m DM/ GeV)(Eν /Eν 0)2 and σ DM–ν,4 < 7 × 10-59 cm2 (m DM/GeV)(Eν /Eν 0)4.