A Decay Chain Spin Analysis for SUSY and UED at the LHC

TL;DR

This thesis investigates how decay chain angular distributions can distinguish between SUSY and UED models at the LHC by analyzing spin effects and production cross sections of gluinos and KK-gluons.

Contribution

It introduces a method to determine particle spins through decay chain analysis and compares SUSY and UED signatures at the LHC, including cross section calculations.

Findings

Angular distributions differ between SUSY and UED due to coupling structures.

Hadronic UED cross section for KK-gluon KK-quark collisions calculated and compared to SUSY.

Boost effects are less significant than angular distribution differences.

Abstract

In this thesis we concentrate on the determination of the spin of an intermediate particle by using a decay chain. In SUSY the gluino is especially interesting for searches at the LHC, since it is a Majorana fermion which can produce like-sign dileptons in the final state. In UED the like-sign dilepton signature could occur as well from the decay of a bosonic KK-gluon. As we will show, angular distributions of the outgoing b-jets in SUSY and UED differ due to the different coupling structures. The effect from the different boosts of gluino and heavy gluon is shown to be much smaller. The hadronic UED cross section for KK-gluon KK-quark collisions is calculated in leading order and compared to the gluino squark collision in SUSY. The analytically given partonic cross sections are compared at the threshold.