Dark Matter in SUGRA, Strings and Branes
  A brief review is given of dark matter in SUGRA, strings and branes. For SUGRA models the implications of Yukawa coupling unification on dark matter are discussed in the light of $g-2$ and $b\to s\gamma$ constraints. A brief discussion is given of the dark matter in orbifold string compactifications under constraints of modular invariance and radiative breaking of the electroweak symmetry. Finally a new candidate for dark matter - an extra-weakly interacting massive particle or an XWIMP- is discussed. Such dark matter can arise in a wide class of models, including the Stueckelberg extensions of MSSM, in U(1) extensions of MSSM with off diagonal kinetic energy, and possibly in a wider class of models which may have a string/D-brane origin. Satisfaction of the relic density of XWIMPs consistent with WMAP is also discussed. 
Pran Nath