Extra-Dimensions and Dark Matter

In this paper we study the general scenario of an effective theory coming from the compactification of a higher dimensional theory in a string inspired setting. This leads to gauge coupling unification at an intermediate mass scale. After having computed all the threshold corrections (due to Kaluza-Klein modes) to the running of the couplings of the MSSM we embark in a detailed phenomenological analysis of the model, based on the numerical package DarkSUSY, to find constraints on the scenario from Dark Matter data. The mass spectrum of the theory does not have tachyons. Moreover we find that the neutralino is still the LSP with a relic density compatible with the most recent experimental data. With respect to the standard mSUGRA scenario we find that the neutralino is higgsino like in most of the parameter space. Our modifications to the DarkSUSY package will be shortly available upon request.