Naturally light higgs doublets in the supersymmetric grand unified theories with dynamical symmetry breaking

We construct a supersymmetric grand unified model in which a dynamical symmetry breaking of SU(5)GUT generates large masses for color-triplet Higgs multiplets while keeping SU(2)l-doublet Higgs multiplets naturally light. The vanishing masses for the Higgs doublets are guaranteed by the Peccei-Quinn symmetry. We also show that the Peccei-Quinn symmetry suppresses the dangerous dimension 5 operators for the nucleon decay.