Radiative corrections to the Yukawa coupling constants in two Higgs doublet models

We calculate one-loop corrected Yukawa coupling constants hff¯ for the standard model-like Higgs boson h   in two Higgs doublet models. We focus on the models with the softly-broken Z2Z2 symmetry, which is imposed to avoid the flavor changing neutral current. Under the Z2Z2 symmetry, there are four types of Yukawa interactions. We find that one-loop contributions from extra Higgs bosons modify the hff¯ couplings to be maximally about 5%5% under the constraint from perturbative unitarity and vacuum stability. Our results show that the pattern of tree-level deviations by the mixing effect in each type of Yukawa couplings from the SM predictions does not change even including radiative corrections. Moreover, when the gauge couplings hVV   (V=W,ZV=W,Z) are found to be slightly (with a percent level) different from the SM predictions, the hff¯ couplings also deviate but more largely. Therefore, in such a case, not only can we determine the type of Yukawa couplings but also we can obtain information on the extra Higgs bosons by comparing the predictions with precisely measured hff¯ and hVV couplings at future electron–positron colliders.