Top—Higgs ht^0 and the Process γγ→ZZ

In the context of topcolor-assisted technicolor(TC2) models,we calculate the s-channel contributions of the top-Higgs ht^0 to the process γγ→ZZ.We find that,for reasonable ranges of the paramters,ht^0 can give significant contributions to this process,when the top-Higgs mass approximately equals to the center-of-mass energy s and the free parameter e=0.01,the cross section can reach 161 fb.which may be detected in the γγ collisions based on the future e+e- colliders.Thus,the process γγ→ZZ may be used to probe the top-Higgs and further test TC2 models in γγ collisions.