WW dibosons at the LHCb experiment

McSkelly, Ben
WW dibosons at the LHCb experiment. PhD thesis, University of Liverpool.

[img] Text
McSkellyBen_May2015_2011180.pdf - Unspecified
Available under License Creative Commons Attribution.

Download (4MB)


The Large Hadron Collider (LHC) is a proton-proton collider that has achieved a world high centre of mass energy. The protons are collided at four distinct detectors. One such is the ATLAS, a large general purpose detector aimed at a multitude of physics analyses. At the start of this PhD, work was undertaken searching for supersymmetry at the ATLAS experiment. After calculating the rates of various processes for wider use, work was undertaken searching for pair production of stops, the supersymmetric partners of top particles. A two lepton stop particle analysis is presented with focus on data driven estimates of electroweak backgrounds. The main analysis in this thesis was conducted using the LHCb experiment. LHCb is a precision detector focusing on events in the forward region. Although primarily designed for B physics, high precision LHCb tracking and vertex resolution allows for electroweak measurements probing proton parton distribution functions at low values of Bjorken-x. A method for measurement of the fiducial cross section of WW events with eta > 2 is presented. The electron-muon channel is chosen due to lower background rates. Events with no jet content and a pair of high momentum leptons originating from the same vertex are selected. The measurement suffers from a small statistical sample, but nevertheless measures a fiducial cross section at 8TeV = 4.7 +-1.5 (stat.) +-0.5(syst.) +-0.1(lumi.) fb consistent with the standard model prediction. Finally, the future of diboson measurements at LHCb is assessed. Further LHCb runs due to begin imminently, will provide sufficient data to alleviate statistical limits and produce competitive measurements.

Item Type: Thesis (PhD)
Additional Information: Date: 2015-01 (completed)
Subjects: ?? QC ??
Depositing User: Symplectic Admin
Date Deposited: 03 Aug 2015 09:11
Last Modified: 17 Dec 2022 01:33
DOI: 10.17638/02011180
URI: https://livrepository.liverpool.ac.uk/id/eprint/2011180