Constraints on models with universal extra dimensions from dilepton searches at the LHC

TL;DR

This paper investigates how LHC dilepton resonance searches can constrain models with universal extra dimensions by focusing on second Kaluza-Klein states that decay into Standard Model particles, providing stronger detection sensitivity.

Contribution

It introduces a novel approach to constrain universal extra dimension models using second Kaluza-Klein states decaying into dileptons, improving detection prospects over traditional missing energy searches.

Findings

Limits on the compactification scale > 715 GeV

Second Kaluza-Klein particle masses > 1.4 TeV

Enhanced sensitivity compared to first Kaluza-Klein searches

Abstract

Models with universal extra dimensions predict that each Standard Model particle is accompanied by a tower of Kaluza-Klein resonances. Canonical searches for the production and cascade decays of first Kaluza-Klein modes through missing transverse momentum signatures suffer in general from low detection efficiencies because of the rather compressed Kaluza-Klein particle mass spectrum. Here, instead we analyze signatures from the production of second Kaluza-Klein states which can decay into Standard Model particles and thus do not result in any missing transverse momentum. Such signatures provide a strong sensitivity, and are of particular interest as they would allow for a clear distinction between extra dimension models and other models of new physics like supersymmetry. We constrain the production of second Kaluza-Klein particles from recent LHC searches for dilepton resonances, and place limits on the compactification scale to be larger than 715GeV, and on the masses of the second Kaluza-Klein particles to be larger than 1.4TeV.