Kaluza-Klein gluon and b-jet forward-backward asymmetry

TL;DR

This paper explores whether a Kaluza-Klein gluon in a warped extra dimension model can explain the observed forward-backward asymmetry of b-quark jets at LEP/SLD, suggesting a KK gluon mass of a few hundred GeV.

Contribution

It proposes a new explanation for the bb data using KK gluons in a Randall-Sundrum model with specific quark couplings, fitting the experimental anomaly.

Findings

KK gluon can account for the bb deviation with a mass of a few hundred GeV.

The model's compatibility with collider constraints is analyzed.

Strong coupling to b-quarks is essential for explaining the asymmetry.

Abstract

The forward-backward asymmetry of $b$-quark jets on the $Z$-pole measured at LEP/SLD experiments shows us -2.8-$\sigma$ deviation from the Standard Model (SM) prediction. We examine a possibility of Kaluza-Klein (KK) gluon to explain the $\afbb$ data in a scenario based on the warped extra dimension model by Randall and Sundrum. In this scenario, the KK gluon strongly couples to $b$-quark by an appropriate choice of the bulk quark mass terms. We find that the $\afbb$ data could be explained if the KK gluon mass is few hundred GeV. Constraints on our scenario from the hadron collider experiments are discussed.