Higher dimensional operators and low energy left-right symmetry

Abstract We consider higher dimensional operators due to quantum gravity or spontaneous compactification of extra dimensions in Kaluza-Klein type theory and their effect in the SO(10) lagrangian. These operators change the boundary conditions at the unification scale. As a result one can allow left-right symmetry to survive till very low energy (as low as ∼ TeV) for a wide range of values for the coupling of these higher dimensional operators and still make the theory compatible with the latest values of sin 2 θ w and α s derived from LEP. We consider both non-supersymmetric and supersymmetric cases with standard Higgses. Proton lifetime is very large in these theories.