Searching for Susy Dark Matter — The Directional Rate and the Modulation Effect

Abstract

The direct detection of dark matter is central to particle physics and cosmology. Current fashionable supersymmetric models provide a natural dark matter candidate which is the lightest supersymmetric particle (LSP). Such models combined with fairly well understood physics like the quark substructure of the nucleon and the structure of the nucleus (form factor and/or spin response function), permit the evaluation of the event rate for LSP-nucleus elastic scattering. The thus obtained event rates are, however, very low or even undetectable. So it is imperative to exploit characteristic signatures, like the modulation effect, i.e., the dependence of the event rate on the earth’s annual motion, and the directional rate, i.e its dependence on the direction of the recoiling nucleus. In this paper we do this using various velocity distributions, isothermal (symmetric as well as only axially asymmetric) and non isothermal (e.g. due to caustic rings).