Measurement of the differential angular distribution of the W boson produced in association with jets in proton-antiproton collisions at sqrt (s)= 1.8 TeV

The full differential cross section of the W boson produced in a proton-antiproton collider can be written as a sum of nine terms. Each term is a product of an analytical expression of the azimuthal and polar angles (cp and 0) of the charged lepton from the W decay measured in the W-rest frame (leptonic part) times a helicity cross section (hadronic part). By dividing the helicity cross sections by the full unpolarized cross section we end up with eight angular coefficients (A0 - A7), which describe theW decay distribution. At low W transverse momentum, only one of the angular coefficients is non-zero. In order to study all the coefficients, we need to study the production of the W at high transverse momentum, in association with the production of jets that balance this transverse momentum. In this thesis we present the first measurement of the A2 and A3 angular coefficients, for four ranges of the W transverse momentum p}f. We performed the analysis on CDF Run Ia and Run Ib W --+ eve data (integrated luminosity of 110 pb-1 ) and W -> uvu data (integrated luminosity of 107 pb-1) with the requirement for the existence of at least one jet passing the CDF jet requirements. We directly measure the cp angle of the charged lepton in the Collins-Soper W rest-frame. In this frame, cp is exactly known, in spite of our ignorance of the longitudinal momentum of the decay neutrino. Moreover, theW-mass systematic uncertainty on the measured azimuthal angle is negligible. We extract measurements for the electron and muon channel W decays, and the statistical combination of the two. We also present the Standard Model prediction for the W angular coefficients Ai as a function of p}f, using a W +jet Monte Carlo event generator, which includes gluon loops. The prediction for three of the angular coefficients (A1 , A4 and A6 ) is presented for the first time.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2012

Author dc:creator

• Strologas, John

Contributors dc:contributor

• Errede, Steven M.

• transverse momentum
• bosons
• particle physics
• W boson
• proton-antiproton collisions

Statement dc:rights

• © Copyright by John Strologas, 2002

Language dc:language

en

Identifier

4591835

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/30824