HIGHER-DIMENSIONAL OPERATORS AND LOW-ENERGY LEFT-RIGHT SYMMETRY

We consider higher dimensional operators due to quantum gravity or spo ntaneous compactification of extra dimensions in Kaluza-Klein type the ory 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 a pproximately TeV) for a wide range of values for the coupling of these higher dimensional operators and still make the theory compatible wit h the latest values of sin2theta(w) and alpha(s) derived from LEP. We consider both non-supersymmetric and supersymmetric cases with standar d Higgses. Proton lifetime is very large in these theories.