On Diurnal and Annual Variations of Directional Detection Rates of Dark Matter

Understand

Direction sensitive direct detection of Weakly Interacting Massive Particles (WIMPs) as dark matter would provide an unambiguous non-gravitational signature of dark matter (DM).

• The diurnal variation of DM signal due to earth's rotation around its own axis can be a significant signature for galactic WIMPs.
• Because of particular orientation of earth's axis of rotation with respect to WIMP wind direction, the apparent direction of WIMP wind as observed at a detector can alter widely over a day.
• In this work we calculate the directional detection rates with their daily and yearly modulations in earth-bound dark matter experiments considering detailed features of the geometry and dynamics of the earth-sun system along with the solar motion in galactic frame.