MSSM apply to a large extent to the (M+1)SSM as well! Still, if supersymmetry is found, one can go further and look for some peculiarites that could distinguish the two kind of models, specially in the case in which the lightest supersymmetric particle is the singlet fermion, or singlino. The (M+1)SSM can also be experimentally tested from the fact that the effective parameters in the equivalent MSSM are very constrained.

The present paper is devoted to a thorough discussion of the model in its version with only dimensionless couplings in its superpotential, and universal boundary conditions for the soft supersymmetric breaking terms at the GUT scale. With these assumptions, the dimensionality of the parameter space of the (M+1)SSM equals that of the MSSM. Our aim is to understand the pattern of the particle spectrum, correlations among the particle masses, and features which are in common with or different from the MSSM. An analysis of the complete parameters space of the model requires numerical methods, as a scanning over the independent parameters at the GUT scale, their subsequent evolution using the RGE down to the weak scale, the minimization of the Higgs potential, the implementation of theoretical and experimental constraints and 