Probing the radion-Higgs mixing at photon colliders

In the Randall-Sundrum model, the radion-Higgs mixing is weakly suppressed by the effective electroweak scale. A novel feature of the gravity-scalar mixing would be a sizable three-point vertex of hμν(n)-h-. We explore the potential of photon colliders, achieved by the laser back-scattering technique, in probing the radion-Higgs mixing via the associated production of the radion with the Higgs boson. The advantage of photon colliders is the capability of adjusting the polarization of the incoming photons such that the signal of the spin-2 graviton exchange can be largely enhanced. The enhancement factor is shown to be about 5, except for the small-ξ region. We also study the corresponding backgrounds step by step in detail.