Vector boson production with the ALICE detector

The main objective of this thesis is to study and investigate the production of massive vector bosons (W+ and W−). This a priori mentioned production is not sensitive to hot nuclear matter effects because of the weak coupling nature of these vector bosons. Thus, in heavy ion collisions they provide a good reference for the medium-induced effects on other probes. The production mechanism of these vector bosons is highly isospin dependent and thus they are affected by the initial state effects. Initial state effects include isospin, Fermi motion, EMC effect, shadowing and nuclear absorption. Hence their production in lead-lead (Pb-Pb) and proton-lead (p-Pb) collisions can be used to test some of these initial state effects. In this thesis only two of these initial state effects will be considered namely, isospin and shadowing (referring to shadowing and anti-shadowing). Eke, these vector bosons can be used to provide a non-arbitrary reference to the probes affected by the medium. Traditionally, in heavy ion collisions, hard processes are expected to scale with the number of binary collision thus a precise study of these vector bosons can be used to test the factorisation assumed in models used to determine centrality. This unique property of electroweak (W) bosons makes them essential probes to study the possible inherent bias in centrality determination. In proton-proton (pp) collisions, their production can be used to obtain information on quark parton distribution functions (PDF). The data used in the analysis was collected by A Large Ion Collider Experiment (ALICE) at the Large Hadron Collider (LHC). The ALICE detector is designed to study ultrarelativistic heavy-ion collisions, in which a hot and dense, strongly-interacting medium is created. The production of W bosons is studied in p-Pb, p-p and Pb-Pb collisions at 5.023, 8 and 5.023 TeV centre-of-mass energies, respectively. The forward muon spectrometer with the pseudorapidity acceptance −4.0 < ŋ < −2.5 is used. W bosons are studied via the inclusive single muon differential pT spectrum.

Grantor dc:publisher.institution

Department of Physics

Year dc:date.issued

2017

Author dc:creator

• Senosi, Kgotlaesele Johnson

Advisors dc:contributor.advisor

• Cleymans, Jean
• Buthelezi, E

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/27310

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/27310