Neutron electric dipole moment in two Higgs doublet model.

We study the effect of the ”chromo-electric” dipole moment on the electric dipole moment(EDM) of the neutron in the two Higgs doublet model. We systematically investigate the Weinberg’s operator O3g = GG ˜ G and the operator Oqg = qσ ˜ Gq, in the cases of tan β ≫ 1, tan β ≪ 1 and tan β ≃ 1. It is shown that Osg gives the main contribution to the neutron EDM compared to the other operators, and also that the contributions of Oug and O3g cancel out each other. It is pointed out that the inclusion of second lightest neutral Higgs scalar adding to the lightest one is of essential importance to estimate the neutron EDM. The neutron EDM is considerably reduced due to the destructive contribution with each other if the mass difference of the two Higgs scalars is of the order O(50GeV).