Constraints on Light Dark Matter From Core-Collapse Supernovae

TL;DR

If light dark matter particles are lighter than approximately or = 10 MeV and reproduce the observed dark matter relic density, supernovae would cool on a much longer time scale and would emit neutrinos with significantly smaller energies than in the standard scenario, in disagreement with observations.

Abstract

We show that light ($\simeq$ 1 -- 30 MeV) dark matter particles can play a significant role in core-collapse supernovae, if they have relatively large annihilation and scattering cross sections, as compared to neutrinos. We find that if such particles are lighter than $\simeq$ 10 MeV and reproduce the observed dark matter relic density, supernovae would cool on a much longer time scale and would emit neutrinos with significantly smaller energies than in the standard scenario, in disagreement with observations. This constraint may be avoided, however, in certain situations for which the neutrino--dark matter scattering cross sections remain comparatively small.

Figures (1)

• Figure 1: Temperature of the LDM-sphere $\,T_{DMS}\,$ for $\,\sigma_{\rm ann}v_{\rm r}\propto v^2$ ($P$-wave), normalized so as to lead to the observed relic density of dark matter. The dashed lines represent various hypothesis for the LDM-nucleon elastic scattering cross section, taken to be $\,\propto T^2$ and (from top to bottom) 1, 10, $10^2$, 10$^3$, 10$^4$, and 10$^5$ times larger than the corresponding neutrino-nucleon cross section. The solid line shows the case of a massive $\nu_\tau$, for comparison.