Flavour Changing Neutral Current Constraints from Kaluza-Klein Gluons and Quark Mass Matrices in RS1

TL;DR

This paper investigates the constraints on quark mass matrices and flavor-changing processes in the Randall-Sundrum model, focusing on KK gluon decays and their implications for flavor physics at the LHC.

Contribution

It identifies viable asymmetric quark mass matrices compatible with flavor constraints and analyzes KK gluon decay signatures to probe flavor structure in RS models.

Findings

Only asymmetric mass matrices from anarchical Yukawas are viable at TeV scale.

Decay ratios of KK gluons into quark pairs can reveal flavor couplings.

Measurement of top quark spin in KK gluon decays can determine chiral couplings.

Abstract

We continue our previous study on what are the allowed forms of quark mass matrices in the Randall-Sundrum (RS) framework that can reproduce the experimentally observed quark mass spectrum and the CKM mixing pattern. We study the constraints the $\Delta F = 2$ processes in the neutral meson sector placed on the admissible forms found there, and we found only the asymmetrical type of quark mass matrices arising from anarchical Yukawa structures stay viable at the few TeV scale reachable at the LHC. We study also the decay of the first Kaluza-Klein (KK) excitation of the gluon. We give the decay branching ratios into quark pairs, and we point out that measurements of the decay width and just one of the quark spins in the dominant $\bar{t}t$ decays can be used to extract the effective coupling of the first KK gluon to top quarks for both chiralities. This provides further probe to the flavour structure of the RS framework.