Determining the Chirality of Yukawa Couplings via Single Charged Higgs   Boson Production in Polarized Photon Collision
  When the charged Higgs boson is too heavy to be produced in pairs, the predominant production mechanism at Linear Colliders is via the single charged Higgs boson production processes, such as $e^-e^+ \to b \bar c H^+, \tau \bar \nu H^+$ and $\gamma\gamma \to b \bar c H^+, \tau \bar \nu H^+$. We show that the yield of a heavy charged Higgs boson at a $\gamma\gamma$ collider is typically one or two orders of magnitude larger than that at an $e^-e^+$ collider. Furthermore, a polarized $\gamma\gamma$ collider can determine the chirality of the Yukawa couplings of fermions with charged Higgs boson via single charged Higgs boson production, and thus discriminate models of new physics. 
Hong-Jian He, Shinya Kanemura, C.-P. Yuan