Neutralino dark matter in orbifold scenarios

The direct detection of neutralino dark matter is analysed within the context of orbifold scenarios from the heterotic superstring. In particular, the theoretical predictions for the neutralinoproton cross section are evaluated and compared with the sensitivity of detectors, taking into account the most recent experimental and astrophysical constraints. In addition to the usual nonuniversalities of the soft terms in orbifold compactifications, due to their modular weight dependence, the contribution of a D-term, generated by the presence of an anomalous U(I) is also investigated. The D-term contribution provides more flexibility in the non-universalities, and is crucial in avoiding dangerous charge and colour-breaking minima. Large neutralino detection cross sections can be obtained in regions of the parameter space fulfilling all experimental and astrophysical constraints thanks to the inclusion of the D-term contribution.