Dependence of dark matter - electron scattering on the galactic dark matter velocity distribution

The rate of dark matter-electron scattering depends on the underlying velocity distribution of the dark matter halo. Importantly, dark matter-electron scattering is particularly sensitive to the high-velocity tail, which differs significantly amongst the various dark matter halo models. In this work, we summarize the leading halo models and discuss the various parameters which enter them. We recommend updated values for these parameters based on recent studies and measurements. Furthermore, we quantify the dependence of the dark matter-electron scattering rate on the choice of halo model and parameters, and demonstrate how these choices propagate to the predicted cross-section limits. The rate is most sensitive to changes in the circular velocity v(0); in silicon targets, we find that the changes in the rate predictions can range from O(0.01%) to O(100%) for contact interactions and O(10%) to O(100%) for long-range interactions.

Automated summary

The rate of dark matter-electron scattering is determined by the velocity distribution of the dark matter halo, particularly the high-velocity tail. Different dark matter halo models result in significant differences in the scattering rate. Updated parameter values based on recent studies are recommended, with the circular velocity v(0) being the most sensitive parameter affecting the rate predictions.