Higgs-radion similarity in production processes involving off-shell fermions

TL;DR

This paper demonstrates that the fermion-radion interaction terms do not affect the production and decay processes of the radion, making its phenomenology similar to that of the Higgs boson in off-shell fermion processes.

Contribution

It shows that additional fermion-radion interaction terms cancel out in perturbative amplitudes, preserving the radion's production and decay characteristics.

Findings

Additional fermion-radion terms cancel in amplitudes for off-shell fermions.

Radion interactions are similar to Higgs interactions despite extra terms.

Radion phenomenology remains unchanged in processes involving off-shell fermions.

Abstract

The appearance of the radion field, which is associated with the spin-0 metric fluctuations combined in some manner with the scalar stabilizing 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 to perturbative amplitudes of physical processes due to these additional terms are canceled out for both massless and massive off-shell fermions. Thus 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.