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Title: Evidence for WZ Production and a Measurement of the WZ Production Cross Section

Abstract

This dissertation describes a test of the Standard Model (SM) of particle physics by measuring the probability, or cross section, of simultaneously producing a W boson and a Z boson from proton-antiproton collisions. The SM predicts the cross section of WZ production to be 3.68 ± 0.25 pb. The SM and physics of WZ production are described in Chapter 2 of this dissertation. The 1.96 TeV center-of-mass energy proton-antiproton collisions are provided by the Fermi National Accelerator Laboratory (FNAL) Tevatron Collider. The W and Z particles are detected using the D0 detector, which is described in Chapter 3. The data were collected by the detector during 2002-2006 corresponding to 1 fb -1 of p{bar p} collisions. This data set is described in Chapter 6. The measurement uses the trilepton (evee, μvee, evμμ, and μvμμ) decay channels, in which a W decays to a charged lepton plus a neutrino and a Z decays to a pair of charged leptons. The W and Z particle selection criteria, detection efficiency, and background determination are described in Chapter 7. We observe 13 candidate events in 1 fb -1 of p$$\bar{p}$$ collisions. In this data set we expect to see 4.5 ± 0.6 background events, and we expect to see 9.2 ± 1.0 signal events. The probability of 4.5 ± 0.6 background events to fluctuate to 13 or more events is 1.2 x 10 -3 which is a 3.0 σ deviation from the background estimate. A log likelihood method is used to determine the most likely cross section as determined by the measured signal efficiencies, the expected backgrounds, and the observed data. Presented in Chapter 8 is a measurement of the cross section for p$$\bar{p}$$ → WZ + X at √s = 1.96 TeV. The WZ diboson production cross section is measured to be σ WZ = 2.7$$+1.7\atop{-1.3}$$ pb. This is in agreement with the predicted Standard Model cross section.

Authors:
 [1]
  1. Univ. of Michigan, Ann Arbor, MI (United States)
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
948180
Report Number(s):
FERMILAB-THESIS-2007-75
TRN: US0901585
DOE Contract Number:  
AC02-07CH11359
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BOSONS; CROSS SECTIONS; DECAY; DETECTION; EFFICIENCY; FERMILAB ACCELERATOR; FERMILAB TEVATRON; INTERMEDIATE BOSONS; LEPTONS; NEUTRINOS; PHYSICS; PROBABILITY; PRODUCTION; STANDARD MODEL; Experiment-HEP

Citation Formats

Degenhardt, James D. Evidence for WZ Production and a Measurement of the WZ Production Cross Section. United States: N. p., 2007. Web. doi:10.2172/948180.
Degenhardt, James D. Evidence for WZ Production and a Measurement of the WZ Production Cross Section. United States. doi:10.2172/948180.
Degenhardt, James D. Tue . "Evidence for WZ Production and a Measurement of the WZ Production Cross Section". United States. doi:10.2172/948180. https://www.osti.gov/servlets/purl/948180.
@article{osti_948180,
title = {Evidence for WZ Production and a Measurement of the WZ Production Cross Section},
author = {Degenhardt, James D.},
abstractNote = {This dissertation describes a test of the Standard Model (SM) of particle physics by measuring the probability, or cross section, of simultaneously producing a W boson and a Z boson from proton-antiproton collisions. The SM predicts the cross section of WZ production to be 3.68 ± 0.25 pb. The SM and physics of WZ production are described in Chapter 2 of this dissertation. The 1.96 TeV center-of-mass energy proton-antiproton collisions are provided by the Fermi National Accelerator Laboratory (FNAL) Tevatron Collider. The W and Z particles are detected using the D0 detector, which is described in Chapter 3. The data were collected by the detector during 2002-2006 corresponding to 1 fb-1 of p{bar p} collisions. This data set is described in Chapter 6. The measurement uses the trilepton (evee, μvee, evμμ, and μvμμ) decay channels, in which a W decays to a charged lepton plus a neutrino and a Z decays to a pair of charged leptons. The W and Z particle selection criteria, detection efficiency, and background determination are described in Chapter 7. We observe 13 candidate events in 1 fb-1 of p$\bar{p}$ collisions. In this data set we expect to see 4.5 ± 0.6 background events, and we expect to see 9.2 ± 1.0 signal events. The probability of 4.5 ± 0.6 background events to fluctuate to 13 or more events is 1.2 x 10-3 which is a 3.0 σ deviation from the background estimate. A log likelihood method is used to determine the most likely cross section as determined by the measured signal efficiencies, the expected backgrounds, and the observed data. Presented in Chapter 8 is a measurement of the cross section for p$\bar{p}$ → WZ + X at √s = 1.96 TeV. The WZ diboson production cross section is measured to be σWZ = 2.7$+1.7\atop{-1.3}$ pb. This is in agreement with the predicted Standard Model cross section.},
doi = {10.2172/948180},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}

Thesis/Dissertation:
Other availability
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