LHC Searches for Top-philic Kaluza-Klein Graviton

TL;DR

This paper investigates the collider phenomenology of a top-philic Kaluza-Klein graviton from Randall-Sundrum models, analyzing current LHC constraints and identifying the most restrictive channels for different graviton masses and couplings.

Contribution

It provides the first detailed analysis of LHC constraints on a top-philic KK graviton with non-universal couplings, highlighting the impact on the cutoff scale and mass limits.

Findings

tar{t} channel gives the strongest constraints

Cutoff scale constrained to around 100 GeV for certain parameters

Mass range of 2-5 TeV for the graviton is still viable

Abstract

We study the phenomenology of a massive graviton $G$ with non-universal couplings to the Standard Model (SM) particles. Such a particle can arise as a warped Kaluza-Klein graviton from a framework of the Randall-Sundrum extra-dimension model. In particular, we consider a case in which $G$ is top-philic, i.e., $G$ interacts strongly with the right-handed top quark, resulting in the large top-loop contributions to its production via the gluon fusion and its decays to the SM gauge bosons. We take into account the constraints from the current 13 TeV LHC data on the channels of $t\bar{t}$, $\gamma\gamma$, $jj (gg)$, $\gamma Z$, and $ZZ$. Consequently, it is found that the strongest limit for this spin-2 resonance $G$ comes from the $t\bar{t}$ pair search, which constrains the cutoff scale to be of ${\cal O}$(100 GeV) for the right-top coupling of ${\cal O}(1)$ and the massive graviton mass in the range $m_G$=2-5 TeV, significantly relaxed compared with the universal $G$ coupling case.