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 $σ_{{\rm DM}\text{-}ν,n}\propto E_ν^n$ $(n=0,2,4)$ at $95\%$ confidence level (CL), $σ_{{\rm DM}\text{-}ν,0}< 10^{-32}\ {\rm cm^2}\ (m_{\rm DM}/{\rm GeV})$, $σ_{{\rm DM}\text{-}ν,2}< 10^{-43}\ {\rm cm^2}\ (m_{\rm DM}/{\rm GeV})(E_ν/E_ν^0)^2$ and $σ_{{\rm DM}\text{-}ν,4}< 10^{-54}\ {\rm cm^2}\ (m_{\rm DM}/{\rm GeV})(E_ν/E_ν^0)^4$, where $E_ν$ is the neutrino energy and $E_ν^0$ is the average momentum of relic cosmic neutrinos today, $E_ν^0 \simeq 6.1\ {\rm K}$. By imposing a satellite forming condition, we obtain the strongest upper bounds on the DM-neutrino cross section at $95\%$ CL, $σ_{{\rm DM}\text{-}ν,0}< 4\times 10^{-34}\ {\rm cm^2}\ (m_{\rm DM}/{\rm GeV})$, $σ_{{\rm DM}\text{-}ν,2}< 10^{-46}\ {\rm cm^2}\ (m_{\rm DM}/{\rm GeV})(E_ν/E_ν^0)^2$ and $σ_{{\rm DM}\text{-}ν,4}< 7\times 10^{-59}\ {\rm cm^2}\ (m_{\rm DM}/{\rm GeV})(E_ν/E_ν^0)^4$.