A new dark matter candidate in the minimal extension of the supersymmetric standard model

We study the cosmology of the neutral supersymmetric fermion sector in the simplest extension of the minimal supersymmetric standard model. We find that in a substantial portion of the allowed parameter space of the model, a new light fermion emerges. For this state we calculate annihilation cross-sections and determine its cosmological abundance. We find that in much of the cosmologically allowed region of parameter space its relic density could be significant enough to solve the dark matter problem.