eCommons

 

Topics In Extensions Of The Standard Model Of Elementary Particles And Their Signatures At The Large Hadron Collider

Other Titles

Abstract

The mechanism for electroweak symmetry breaking (EWSB) is yet unknown and the hierarchy between the EWSB scale and the Planck scale is not understood. Several alternative mechanisms for EWSB were postulated by theorists. In the near future, experiments at the Large Hadron Collider (LHC) at CERN will begin testing these theories. In this thesis, we explore two of the postulated mechanisms, supersymmetry and little Higgs models, and some of their consequences for the experiments at the LHC. The "golden region" in the parameter space of the Minimal Supersymmetric Standard Model is the region where the experimental constraints are satisfied and the amount of fine-tuning is minimized. In this region, the stop trilinear soft term At is large, leading to a signficant mass splitting between the two stop mass eigenstates. As a result, the decay ~t2 -> ~t1 x Z is kinematically allowed. The experiments at the LHC can search for this decay through an inclusive signature, Z + 2jb + ET + X. We evaluate the Standard Model backgrounds and / identify cuts to isolate this signal. We also discuss other possible interpretations of such a signal. We then construct an anomaly-free, weakly-coupled, renormalizable ultraviolet completion of the Littlest Higgs model with T-parity (LHT), based on an SU (5) x SU (2) x U (1) gauge theory with a discrete Z2 symmetry. The model re- produces the complete structure of the LHT below the 10 TeV scale and contains additional states at the 1 TeV scale. We estimate the impact of these states on precision electroweak observables and discuss how the model can be embedded into a supersymmetric theory or a five-dimensional setup with a warped extra dimension. Finally, we investigate the potential of the Compact Muon Solenoid (CMS) detector at the LHC to discriminate between supersymmetric and Little Higgs models. We find that the angular and momentum distributions of the observed jets are sufficient to discriminate between the two models in a simple test case scenario with a few inverse femtobarns of LHC data, provided that these distributions for both models and the dominant Standard Model backgrounds can be reliably predicted by Monte Carlo simulations.

Journal / Series

Volume & Issue

Description

Sponsorship

Date Issued

2009-10-13T13:49:20Z

Publisher

Keywords

Hadron Collider

Location

Effective Date

Expiration Date

Sector

Employer

Union

Union Local

NAICS

Number of Workers

Committee Chair

Committee Co-Chair

Committee Member

Degree Discipline

Degree Name

Degree Level

Related Version

Related DOI

Related To

Related Part

Based on Related Item

Has Other Format(s)

Part of Related Item

Related To

Related Publication(s)

Link(s) to Related Publication(s)

References

Link(s) to Reference(s)

Previously Published As

Government Document

ISBN

ISMN

ISSN

Other Identifiers

Rights

Rights URI

Types

dissertation or thesis

Accessibility Feature

Accessibility Hazard

Accessibility Summary

Link(s) to Catalog Record