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Title: Measurement of the Intermediate Vector - Boson Production Cross Section and Mass at the Fermilab Proton- Anti-proton Collider

Abstract

Production cross sections and masses of the charged and the neutral intermediate vector bosons (IVB's) have been determined through their electron decay channel using the CDF detector at the Fermilab Tevatron, which is the world largest pp collider at the moment.

Authors:
 [1]
+ Show Author Affiliations
  1. Univ. of Tsukuba (Japan)
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1402443
Report Number(s):
FERMILAB-THESIS-1989-10
293061
DOE Contract Number:
AC02-07CH11359
Resource Type:
Thesis/Dissertation
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Morita, Youhei. Measurement of the Intermediate Vector - Boson Production Cross Section and Mass at the Fermilab Proton- Anti-proton Collider. United States: N. p., 1989. Web. doi:2241/5041.
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Morita, Youhei. Measurement of the Intermediate Vector - Boson Production Cross Section and Mass at the Fermilab Proton- Anti-proton Collider. United States. doi:2241/5041.
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Morita, Youhei. Sun . "Measurement of the Intermediate Vector - Boson Production Cross Section and Mass at the Fermilab Proton- Anti-proton Collider". United States. doi:2241/5041. https://www.osti.gov/servlets/purl/1402443.
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@article{osti_1402443,
title = {Measurement of the Intermediate Vector - Boson Production Cross Section and Mass at the Fermilab Proton- Anti-proton Collider},
author = {Morita, Youhei},
abstractNote = {Production cross sections and masses of the charged and the neutral intermediate vector bosons (IVB's) have been determined through their electron decay channel using the CDF detector at the Fermilab Tevatron, which is the world largest pp collider at the moment.},
doi = {2241/5041},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 1989},
month = {Sun Jan 01 00:00:00 EST 1989}
}
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Thesis/Dissertation:
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DOI:  2241/5041
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  • In 1961 Sheldon Lee Glashow, while working on electroweak unification gauge theory, developed a model in which he introduced a massive neutral intermediate vector boson, call Z [1], [2], [3]. By 1967 Steven Weinberg and Abdus Salam had independently solved the theoretical problems with this model and developed their own self-consistent theory. In this thesis the Z gauge boson production rate at CDF as a function of the Z transverse momentum is studied in the dimuon channel.

  • A measurement of the top anti-top quark pair production cross section in pmore » $$\bar{p}$$ collisions at a center-of-mass energy of 1.96 TeV is presented. The measurement is made using data with integrated luminosity of 109.4 pb -1, obtained at the Collider Detector at Fermilab between August 2002 and May 2003. A search is made for the dilepton decay channel of top anti-top production, t$$\bar{t}$$→l+νbl-νl$$\bar{b}$$. The Standard Model dilepton decay channel of the top anti-top quark pair production involves two high transverse momentum leptons, a large missing energy from the undetected neutrinos, two jets from the b and b¯ quark fragmentations. Various Standard Model processes can mimic t$$\bar{t}$$ production in this decay channel. These backgrounds are estimated to be 0.65 ± 0.13 events in an integrated luminosity of 109.4 pb -1. In the data, one ee, three μμ, and two eμ dilepton candidates were observed. From these data, the t$$\bar{t}$$ production cross section of σ t$$\bar{t}$$ =11.4 $$+6.2\atop{-4.6}$$ pb has been measured. This measurement is consistent with the theoretical prediction of the Standard Model, σ t$$\bar{t}$$ =6.70 $$+71\atop{0.88}$$ pb assuming a top quark mass of 175 GeV/c 2.« less

  • Discovery of the top quark in 1995 at the Fermilab Tevatron collider concluded a long search following the 1977 discovery of bottom (b) quark [1] and represents another triumph of the Standard Model (SM) of elementary particles. Top quark is one of the fundamental fermions in the Standard Model of electroweak interactions and is the weak-isospin partner of the bottom quark. A precise measurement of top pair production cross-section would be a test of Quantum Chromodynamics (QCD) prediction. Presently, Tevatron is the world's highest energy collider where protons (p) and anti-protons (more » $$\bar{p}$$) collide at a centre of mass energy √s of 1.96 TeV. At Tevatron top (t) and anti-top ($$\bar{t}$$) quarks are predominantly pair produced through strong interactions--quark annihilation (≅ 85%) and gluon fusion (≅ 15%). Due to the large mass of top quark, t or $$\bar{t}$$ decays (~ 10 -25 sec) before hadronization and in SM framework, it decays to a W boson and a b quark with ~ 100% branching ratio (BR). The subsequent decay of W boson determines the major signatures of t$$\bar{t}$$ decay. If both W bosons (coming from t and $$\bar{t}$$ decays) decay into leptons (viz., ev e, μv μ or τc τ) the corresponding t$$\bar{t}$$ decay is called dileptonic decay. Of all dileptonic decay modes of t$$\bar{t}$$, the t$$\bar{t}$$ → WWb$$\bar{b}$$ → ev eμv μb$$\bar{b}$$ (eμ channel) decay mode has the smallest background contamination from Z 0 production or Drell-Yan process; simultaneously, it has the highest BR (~ 3.16%) [2] amongst all dileptonic decay modes of t$$\bar{t}$$. During Run I (1992-1996) of Tevatron, three eμ candidate events were detected by D0 experiment, out of 80 candidate events (inclusive of all decay modes of t$$\bar{t}$$). Due to the rarity of the t$$\bar{t}$$ events, the measured cross-section has large uncertainty in its value (viz., 5.69 ± 1.21(stat) ± 1.04(sys) pb {at} √s = 1.8 TeV measured by D0 [3]). This analysis presents a cross section measurement in eμ channel utilizing ~ 228 pb -1 of data collected by D0 experiment during Tevatron Run II (between June 2002 and April 2004).« less

  • In this dissertation we report on a measurement of the proton antiproton total cross section,more » $$\sigma_{tot}$$, taken at a center of mass energy $$\sqrt{s}$$=l.8Tev and performed at the TEVATRON Collider by the members of the E710 collaboration....« less

  • We discuss the measurement of the cross section for tmore » $$\bar{t}$$ production in p$$\bar{p}$$ collisions at √s = 1.96 TeV in e+jets final states observed at the D0 experiment at the Fermilab Tevatron. Our result is based on data collected from the June 2002 to September 2003 period of Run II of the p$$\bar{p}$$ Collider. In the Standard Model, the top quark is expected to decay mainly into a W boson and a b quark. The W boson can decay subsequently into a lepton and its neutrino or a q$$\bar{q}$$ quark-antiquark pair. In this thesis, we focus on the e + v e or e - $$\bar{v}$$ e decays of one of the W bosons and the q$$\bar{q}$$ decays of the other W boson in t$$\bar{t}$$ final states. The b, q and q' quarks appear as jets of particles in the detector, thereby defining the e+jets final state. We present two methods used for performing this measurement. The first method is based on a Random Grid Search (RGS) that minimizes the uncertainty on the extracted cross section. The variables used in the search take advantage of differences between expected background and signal processes to obtain the yield of t$$\bar{t}$$ events. The second method uses a Neural Network (NN) procedure that discriminates signal from background through the application of a NN trained on simulated t$$\bar{t}$$ signal and W+jets background events. The preliminary results presented in this thesis for inclusive t$$\bar{t}$$ production are σ p$$\bar{p}$$ → t$$\bar{t}$$ + x of 7.9$$+2.6\atop{-2.4}$$(stat) $$+2.2\atop{-2.3}$$(syst) ± 0.5 (L) pb for the NN analysis, where the uncertainties correspond to contributions from statistical and systematic sources and from the uncertainty on luminosity. Our measurements are consistent with each other, and are within error of the value of 6.77 ± 0.42 pb expected in the Standard Model.« less