Skobeltsyn Institute of Nuclear Physics
Lomonosov Moscow State University

The appearance of the radion field and of the radion, the corresponding lowest Kaluza-Klein (KK) mode, is a generic prediction of stabilized brane world models. In such models the radion plays the role of the dilaton, and its mass may be somewhat smaller than that of all the KK modes of other particles propagating in the multidimensional bulk. Due to its origin, the radion couples to the trace of the energy-momentum tensor of the Standard Model, the interaction Lagrangian of the radion and the Standard Model fermions being similar to that of the SM Higgs-fermion interactions except for additional terms, which come into play only in the case of off-shell fermions. In the present paper it is shown that all the contributions due to these additional terms to perturbative amplitudes of physical processes with emitted single radion and an arbitrary number of gauge bosons are canceled out for both massless and massive off-shell fermions. Thus in this case the additional fermion-radion terms in the interaction Lagrangian do not alter any production and decay properties of the radion compared to those of the Higgs boson.