WIMP Direct Detection:. Halo Modelling and Small Scale Structure
Abstract
Weakly Interacting Massive Particle (WIMP) direct detection strategies and data analyses are often based on the simplifying assumption of a standard spherical, isotropic halo model, but observations and numerical simulations indicate that galaxy halos are in fact triaxial and anisotropic and contain substructure. The annual modulation of the event rate (due to the motion of the Earth) provides a potential WIMP `smoking gun', however this signal depends sensitively on the local WIMP velocity distribution. I briefly review observations and numerical simulations of the stucture of dark matter halos and the construction of halo models. I then discuss the effect of two specific models (with parameters chosen to reproduce the properties of observed and simulated halos) on exclusions limits and the annual modulation signal. Exclusion limits undergo a relatively small (halo model and experiment dependent) change of shape. The phase and amplitude of the annual modulation signal can change significantly, however. Finally I discuss the possibility that the dark matter distribution is not completely smooth on the very small (sub-mpc) scales probed by WIMP direct detection.
- Publication:
-
The Identification of Dark Matter
- Pub Date:
- April 2005
- DOI:
- 10.1142/9789812701848_0043
- Bibcode:
- 2005idm..conf..295G