Searching for an anomalous $\bar{t}q\gamma$ coupling via single top quark production at a $\gamma \gamma$ collider

We investigate the potential of a high-energy $\gamma \gamma$ collider to detect an anomalous $\bar{t}q\gamma$ coupling from observation of the reaction $\gamma \gamma \to t\bar{q}$, $\bar{t}q$, where $q=c$ or $u$. We find that with $b$-tagging and suitable kinematic cuts this process should be observable if the anomalous coupling $\kappa \mathrm{/}\mathrm{\Lambda }$ is no less than about 0.05/TeV, where $\mathrm{\Lambda }$ is the scale of new physics associated with the anomalous interaction. This improves upon the bound possible from observation of top decays at the Tevatron.