Radion Mediated Flavor Changing Neutral Currents

TL;DR

This paper analyzes the flavor-changing couplings of the Radion in warped extra-dimensional models, showing how these couplings depend on fermion bulk parameters and can be constrained by experiments or observed at the LHC.

Contribution

It derives the general flavor structure of Radion-fermion couplings in warped extra dimensions, independent of the Higgs localization, and explores their experimental implications.

Findings

Radion-fermion couplings are generically misaligned with fermion masses.

Flavor-changing couplings are constrained by $ riangle F=2$ experimental bounds.

Heavy Radion decays into top and charm quarks could be observable at the LHC.

Abstract

In the context of a warped extra-dimension with Standard Model fields in the bulk, we obtain the general flavor structure of the Radion couplings to fermions and show that the result is independent on the particular nature of the Higgs mechanism (bulk or brane localized). These couplings will be generically misaligned with respect to the fermion mass matrix when the fermion bulk mass parameters are not all degenerate. When the Radion is light enough, the generic size of these tree-level flavor changing couplings will be strongly constrained by the experimental bounds on $\Delta F=2$ processes. At the LHC the possibility of a heavier Radion decaying into top and charm quarks is then considered as a promising signal to probe the flavor structure of both the Radion sector and the whole scenario.