Gravitational Focusing and Substructure Effects on the Rate Modulation in Direct Dark Matter Searches

TL;DR

This paper investigates how gravitational focusing by the Sun influences the annual and biannual modulation signals in direct dark matter detection, especially considering local dark matter substructures like the Sagittarius stream and dark disk.

Contribution

It provides a detailed analysis of the impact of gravitational focusing on dark matter signal modulation in the presence of substructure, highlighting the suppression of certain features.

Findings

GF alters the expected modulation signals

Substructure features are partially suppressed by GF

Some distinguishing signals remain despite GF effects

Abstract

We study how gravitational focusing (GF) of dark matter by the Sun affects the annual and biannual modulation of the expected signal in non-directional direct dark matter searches, in the presence of dark matter substructure in the local dark halo. We consider the Sagittarius stream and a possible dark disk, and show that GF suppresses some, but not all, of the distinguishing features that would characterize substructure of the dark halo were GF neglected.