Modulation Effect with Realistic Velocity Dispersion of Supersymmetric Dark Matter

The direct detection of supersymmetric dark matter is central to particle physics and cosmology. Since the expected event rates are very small, one may exploit the dependence of the event rate on the Earth's motion (modulation effect). We study this effect, on both nondirectional and directional experiments, with realistic (asymmetric) velocity distributions considering all components of the Earth's velocity. These defects combined lead to fivefold enhancement, i.e., a modulation amplitude as large as $46\%$.