Relic density of dark matter in the next-to-minimal supersymmetric standard model -: art. no. 001

We present a code for computing the relic density of dark matter in the next-to-minimal supersymmetric standard model (NMSSM). Dominant corrections to the Higgs masses are calculated with NMHDECAY as well as theoretical and collider constraints. All neutralino annihilation and coannihilation processes are then computed with an extended version of micrOMEGAs, taking into account higher order corrections to Higgs vertices. We explore the parameter space of the NMSSM and consider in particular the case of a bino LSP, of a mixed bino-higgsino LSP and of a singlino LSP. As compared to the case for the MSSM, neutralino annihilation is often more efficient, as it can take place via (additional) Higgs resonances as well as annihilation into light Higgs states. Models with a large singlino component can be compatible with WMAP constraints.