Axion, Neutrinos Masses and $\mu$-Problem in Minimal Supersymmetric Standard Model (MSSM)

We review very nice mechanism to generate masses to all the neutrinos in the Minimal Supersymmetric Standard Model (MSSM) without break $R$-parity. In consequence we get viable axion as Dark Matter candidate and at the same time solve the $\mu$-problem in a similar way as done in the Next to Minimal Supersymmetric Model (NMSSM).