Speaker
Description
Abstract
The Sun provides a complementary probe of sub-GeV dark matter (DM) through spin-dependent DM–proton scattering and neutrinos from DM annihilation. For $m_\chi \lesssim 4\ \mathrm{GeV}$, where evaporation is significant, the spatial distribution of the captured DM population is a key uncertainty in predicting the annihilation rate and neutrino flux. We use DaMaSCUS-SUN to perform Monte Carlo trajectory simulations for $m_\chi = 0.1–4\ \mathrm{GeV}$, following DM capture, scattering, thermalization and evaporation without assuming an equilibrium density profile or Knudsen interpolation. We find systematic, order-unity deviations from the conventional Knudsen-interpolated density profile in the optically thin, evaporation-dominated regime. These deviations are driven primarily by evaporation, while incomplete thermalization plays a secondary role by leaving a residual fraction of DM on extended, non-thermal orbits. Our results provide a direct simulation-based test of the assumptions underlying current solar DM limits below 4 GeV and have implications for the robustness of neutrino-based constraints in this mass range.
