Phenomenological viability of neutralino dark matter in the next-to-minimal supersymmetric standard model

The viability of the lightest neutralino as a dark matter candidate in the next-to-minimal supersymmetric standard model is analysed. We carry out a thorough analysis of the parameter space, taking into account accelerator constraints as well as bounds on low-energy observables, such as the muon anomalous magnetic moment and rare K and B meson decays. The neutralino relic density is also evaluated and consistency with present bounds imposed. Finally, the neutralino direct detection cross section is calculated in the allowed regions of the parameter space and compared to the sensitivities of present and projected dark matter experiments. Regions of the parameter space are found where experimental constraints are fulfilled, the lightest neutralino has the correct relic abundance and its detection cross section is within the reach of dark matter detectors. This is possible in the presence of very light singlet-like Higgses and when the neutralino is either light enough so that some annihilation channels are kinematically forbidden, or has a large singlino component.