Lightest Kaluza-Klein graviton mode in a backreacted Randall-Sundrum scenario

TL;DR

This paper investigates how the backreaction of a stabilising scalar field in the Randall-Sundrum model suppresses the coupling of the lightest KK graviton with standard model particles, affecting collider search signals.

Contribution

It demonstrates that backreaction effects significantly weaken KK graviton signals in collider experiments, highlighting the importance of modulus stabilisation in warped extra dimension searches.

Findings

Backreaction suppresses KK graviton coupling to SM matter.

Suppressed couplings explain non-detection in colliders.

Modulus stabilisation is crucial for accurate phenomenological predictions.

Abstract

In search of extra dimensions in the ongoing LHC experiments, signatures of Randall-Sundrum (RS) lightest KK graviton have been one of the main focus in recent years. The recent data from the dilepton decay channel at the LHC has determined the experimental lower bound on the mass of the RS lightest Kaluza-Klein (KK) graviton for different choices of underlying parameters of the theory. In this work we explore the effects of the backreaction of the bulk scalar field, which is employed to stabilise the RS model, in modifying the couplings of the lightest KK graviton with the standard model (SM) matter fields located on the visible brane. In such a modified background geometry we show that the coupling of the lightest KK graviton with the SM matter fields gets a significant suppression due to the inclusion of the backreaction of the bulk stabilising scalar field. This implies that the backreaction parameter weakens the signals from RS scenario in collider experiments which in turn explains the non-visibility of KK graviton in colliders. Thus we show that the modulus stabilisation plays a crucial role in the search of warped extra dimensions in collider experiments.