KK Gravitons at LHC2

TL;DR

This paper investigates the constraints on KK graviton masses and couplings in holographic composite Higgs models using LHC data, finding that 0.5-3 TeV KK gravitons are compatible with current constraints and highlighting promising detection channels.

Contribution

It introduces a method to control KK graviton masses via brane kinetic terms and explores their phenomenology in Little RS models with modified couplings.

Findings

KK gravitons with 0.5-3 TeV masses are compatible with LHC constraints.

Di-photon and ZZ channels are promising for detection.

Little RS models enhance the likelihood of observing KK gravitons.

Abstract

In this work we study constraints from new searches for heavy particles at the LHC on the allowed masses and couplings of a KK Graviton in a holographic composite Higgs model. Keeping new electroweak states heavy such that electroweak precision tests are satisfied, we control the mass of the lightest KK graviton using a brane kinetic term. With this we study KK graviton masses from 0.5-3 TeV. In our analysis we also employ Little Randall-Sundrum (RS) Models, characterised by a lower UV scale in the 5D model which in turn implies modified couplings to massless bulk fields. Viewing this scenario as a strongly coupled 4D theory with a composite Higgs boson, the KK graviton is interpreted as a composite spin-2 state and the varying UV scale corresponds to a varying intermediate scale between the cutoff of the low energy effective theory and the Planck scale. We find that KK gravitons with masses in the range 0.5-3 TeV are compatible with current collider constraints, where the most promising channels for detecting these states are the di-photon and ZZ channels. A detection is more likely in the little RS models, in which the dual gauge theory has a larger number of colours than in traditional RS models.