Dark matter and dark forces from a hidden sector with gravity mediation

Hidden sectors arise naturally in various extensions of the standard model and from string compactifications. Scenarios containing a dark matter particle coupled to a hidden U(1) gauge boson which kinetically mixes with the SM photon are of great interest since they could explain recent terrestrial and astrophysical anomalies, like the e+ e- excesses observed by PAMELA, the annual modulation signal reported by DAMA/LIBRA and the low energy events seen by CoGeNT. The latter two direct detection observations seem to point towards a light dark matter candidate. String theory provides an additional motivation for hidden sectors but interestingly seems to favour models with gravity mediation, rather than gauge mediation which has been generally assumed in the context of light hidden dark matter. Therefore, we construct a light hidden sector in a simple supersymmetric model in which the supersymmetry breaking effects are dominated by gravity mediation and study the phenomenology of the corresponding dark matter particle and the hidden photon, the ''Dark Force''.