Dark Matter in Supersymmetric theories

In this thesis is performed an analysis of supersymmetric dark matter candidates in the framework of the minimal supersymmetric standard model (MSSM) which is the supersymmetric extension of the standard model with the minimal particle content. In this model, each standard model boson (fermion) has a fermionic (bosonic) counterpart with the same quantum numbers, called superpartner. The fact that R-parity conserving MSSM model naturally gives a dark matter candidate, is one of the most successful arguments which favoured this theory as the natural extension of the standard model. On a phenomenological ground the various dark matter candidates are tested with a variety of experimental searches. In particular direct searches try to detect the dark matter particles while they are passing through the Earth measuring the nuclear recoil energies due to the scattering between the dark matter and ordinary matter. Thus in this thesis is investigated the possibility that the dark matter is made up of neutralinos, a mixture of the superpartners of the electrically and color neutral standard model bosons. Scanning over the free parameters of the model are taken into account various particular neutralino configurations. For each case is required that the neutralino relic abundance matches the measured dark matter density and we impose the powerful constraints from direct detection experiments. These analysis are performed both numerically and analytically. The main result of this work is that many of the MSSM dark matter proposal are nearly ruled out by the most recent experimental constraints; Nevertheless some possibilities are still valid such as a particular choice called Well-Tempered neutralino.