Constraints on Randall-Sundrum model from top-antitop production at the LHC

TL;DR

This paper investigates how measurements of top-antitop production at the LHC constrain the parameters of the Randall-Sundrum model, especially the KK graviton excitations and their effects on spin correlations.

Contribution

It provides new bounds on the RS model parameters using LHC data and explores the impact of KK gravitons on top pair spin asymmetry.

Findings

Coupling parameter ($k/ar{M}_{pl}$) excluded from 0.03 to 0.22 depending on $m_1$

LHC measurements significantly restrict RS model parameter space

KK excitations affect top pair spin asymmetry in measurable ways

Abstract

We study the top pair production cross section at the LHC in the context of Randall-Sundrum model including the Kaluza-Klein (KK) excited gravitons. It is shown that the recent measurement of the cross section of this process at the LHC restricts the parameter space in Randall-Sundrum (RS) model considerably. We show that the coupling parameter ($\frac{k}{\bar{M}_{pl}}$) is excluded by this measurement from 0.03 to 0.22 depending on the mass of first KK excited graviton ($m_1$). We also study the effect of KK excitations on the spin correlation of the top pairs. It is shown that the spin asymmetry in $t\bar{t}$ events is sensitive to the RS model parameters with a reasonable choice of model parameters.