Radion Phenomenology with 3 and 4 Generations

TL;DR

This paper investigates the behavior and experimental constraints of the radion in warped extra-dimensional models with three or four fermion families, highlighting flavor violation effects and new decay channels.

Contribution

It provides analytic expressions for radion-fermion couplings in models with three or four families and analyzes the impact of flavor violation on radion phenomenology.

Findings

Updated experimental limits on radion couplings.

Modified radion decay branching ratios including flavor violating channels.

Identification of new decay modes involving fourth-generation fermions.

Abstract

We study radion phenomenology in an warped extra-dimension scenario with Standard Model fields in the bulk, with and without an additional fourth family of fermions. The radion couplings with the fermions will be generically misaligned with respect to the Standard Model fermion mass matrices, therefore producing some amount of flavor violating couplings and potentially influencing production and decay rates of the radion. Simple analytic expressions for the radion-fermion couplings are obtained with three or four families. We also update and analyze the current experimental limits on radion couplings and on the model parameters, again with both three and four families scenarios. We finally present the modified decay branching ratios of the radion with an emphasis on the new channels involving flavor diagonal and flavor violating decays into fourth generation quarks and leptons.