Non-minimal Universal Extra Dimensions: The strongly interacting sector at the Large Hadron Collider

TL;DR

This paper investigates the strongly interacting sector of a non-minimal Universal Extra Dimension model with brane-localized terms, analyzing KK particle masses, interactions, and collider signatures at the LHC to constrain the model.

Contribution

It provides a detailed analysis of the impact of brane-localized kinetic and Yukawa terms on KK excitations and collider phenomenology in nmUED, including cross section calculations and LHC constraints.

Findings

Modified KK gluon and quark masses and couplings due to brane terms

Estimated LHC cross sections for KK particle production and decay

Derived constraints on nmUED parameter space from LHC data

Abstract

We work out the strongly interacting sector of a non-minimal Universal Extra Dimension (nmUED) scenario with one flat extra spatial dimension orbifolded on S^1/Z_2 in the presence of brane-localized kinetic and Yukawa terms. On compactification, these terms are known to have significant, nontrivial impact on the masses and the couplings of the Kaluza-Klein (KK) excitations. We study the masses of the level `1' KK gluon and the quarks and find the modified strong interaction vertices involving these particles. The scenario conserves KK parity. Possibility of significant level-mixing among the quarks from different KK-levels is pointed out with particular reference to the top quark sector. Cross sections for various generic final states involving level `1' KK-gluon and KK-quarks from first two generations are estimated at the Large Hadron Collider (LHC) via an implementation of the scenario in MadGraph-5 with the help of FeynRules. The decay branching fractions of both strong and weakly interacting KK excitations are studied to estimate yields in various different final states involving jets, leptons and missing energy. These are used to put some conservative constraints on the nmUED parameter space using the latest LHC data. Nuances of the scenario are elucidated with reference to the minimal Universal Extra Dimension (mUED) and Supersymmetry (SUSY) and their implications for the LHC are discussed.