Phenomenology of the radion in the Randall–Sundrum scenario at colliders

Phenomenology of a radion (φ) that stabilizes the modulus in the Randall–Sundrum scenario is considered. The radion couples to the trace of energy momentum tensor of the standard model (SM) with a strength suppressed only by a new scale (Λφ) of an order of the electroweak scale. In particular, the effective coupling of a radion to two gluons is enhanced due to the trace anomaly of QCD. Therefore, its production cross section at hadron colliders could be enhanced, and the dominant decay mode of a relatively light radion is φ→gg, unlike the SM Higgs boson case. We also present constraints on the mass mφ and the new scale Λφ from the Higgs search limit at LEP and perturbative unitarity bound.