The SUSY EW-like corrections to top pair production in photon-photon collisions

We studied the one-loop contributions of the gaugino-Higgsino-sector to the process of top-pair production via $\gamma \gamma$ fusion at NLC in frame of the Minimal Supersymmetric Model(MSSM). We find that the corrections to $\gamma \gamma \to t\bar{t}$and$e^+ e^- \to \gamma \gamma \to t\bar{t}$ are found to be significant and can approach to a few percent and one percent, respectively. Furthermore, the dependences of the corrections on the supersymmetric parameters are also investigated. The corrections are not sensitive to $M_{SU(2)}$ (or $\mathrm{\mid }\mu \mathrm{\mid }$) when $M_{SU(2)}>>\mathrm{\mid }\mu \mathrm{\mid }$ (or $\mathrm{\mid }\mu \mathrm{\mid }>>M_{SU(2)}$) and are weakly dependent on the $\tan \beta$ with $M_Q$ (or $\mathrm{\mid }\mu \mathrm{\mid }$) being large enough. But they are sensitive to the c.m.s. energy of the incoming photons.