A singlet extension of the MSSM with a dark matter portal

The minimal extension of the MSSM (NMSSM) has been widely studied in the search for a natural solution to the mu-problem. In this work, we consider a variation of the NMSSM where an additional singlet is added and a Peccei-Quinn symmetry is imposed. We study its neutralino sector and compute the annihilation cross section of the lightest neutralino. We use existent cosmological and collider data to constrain the parameter space and consider the lightest neutralino, with mass between 1 and 15 GeV, as a thermal dark matter candidate.