A probe of the Radion-Higgs mixing in the Randall-Sundrum model at $e^+ e^-$ colliders

In the Randall-Sundrum model, the radion-Higgs mixing is weakly suppressed by the effective electroweak scale. A novel feature of the existence of gravity-scalar mixing would be a sizable three-point vertex, h/sub mu nu //sup (n)/-h- phi . We study this vertex in the process e/sup +/e/sup -/ to h/sub mu nu //sup (n)/ to h phi , which is allowed only with a nonzero radion-Higgs mixing. It is shown that the angular distribution is a unique characteristic of the exchange of massive spin-2 gravitons, and the total cross section at the future e/sup +/e/sup -/ colliders is big enough to cover a large portion of the parameter space that the LEP or LEP II data cannot constrain. (16 refs).