R-Symmetry in the Minimal Supersymmetric Standard Model and Beyond with Several Consequences

The supersymmetric sector of minimal supersymmetric standard model (MSSM) possesses a U(1) R-symmetry which contains Z_2 matter parity. Non-zero neutrino masses, consistent with a 'redefined' R-symmetry, are possible through the see-saw mechanism and/or a pair of superheavy (mass M) SU(2)_L triplets with vev of order M^2_W/M. If this R-symmetry is respected by the higher order terms, then baryon number conservation follows as an immediate consequence. In the presence of right handed neutrinos, the observed baryon asymmetry of the universe arises via leptogenesis. An interplay of R- and Peccei-Quinn symmetry simultaneously resolves the strong CP and mu problems.