Measurement of the W and Z Cross Sections in the Electron Channel for P Anti-p Collisions at S**(1/2)


Book Description

This dissertation presents measurements of the inclusive production cross sections for W and Z gauge bosons decaying through the electron channel with p{bar p} collisions at a center-of-mass energy of 1.96 TeV. The ratio of these cross sections is then used to extract the W total width. The Standard Model (SM) of electroweak and strong interactions is a collection of theories which together encompass what is currently known about the elementary particles that make up matter and the forces through which they interact. Experimentalists are constantly searching for violations of the Standard Model by making precision measurements of predicted interactions. The decay of the W boson is one such interaction. The rate of its decay is reflected in its width which is predicted to high precision using Standard Model-based calculations. Therefore, a high precision experimental width measurement would be very sensitive to any such violation. In principle the W and Z boson production cross sections could also be good Standard Model tests. However, a precise knowledge of integrated luminosity is required which is unfortunately difficult to obtain at the Tevatron. In fact, the W and Z cross section results can be used to obtain a more precise luminosity measurement. The data set consists of a total integrated luminosity of 177 pb{sup -1} collected from September 2002 to September 2003 using the D0 detector at Fermilab.




Measurement of the W and Z Boson Production Cross Sections in P {anti P} Collisions at {radical}s


Book Description

This thesis reports on the measurement of the W and Z boson inclusive production cross sections (?{sub W} and?{sub Z}) times electronic branching ratios (Br(W → e?) and Br(Z → ee)) in p{anti p} collisions at √s = 1.8 TeV. The analysis is based on 12.8 pb−1 of data taken in the 1992-1993 run by the D0 detector at the Fermilab Tevatron collider; the cross sections were measured to be:?{sub W} · Br(W → e?) = 2. 36 ± 0.02 ± 0.07 ± 0.13 nb and?{sub Z} · Br(Z → ee) = 0.218 ± 0.008 ± 0.008 ± 0.012 nb. The first error is statistical, the second error represents the non- luminosity systematic error, and the third error shows the uncertainty in the luminosity determination. Future prospects for similar measurements based on larger samples of data are discussed.




Measurement of the W and Z Boson Production Cross Sections in P[anti P] Collisions At[radical]


Book Description

This thesis reports on the measurement of the W and Z boson inclusive production cross sections ([sigma][sub W] and[sigma][sub Z]) times electronic branching ratios (Br(W[r-arrow] e[nu]) and Br(Z[r-arrow] ee)) in p[anti p] collisions at[radical]s= 1.8 TeV. The analysis is based on 12.8 pb[sup[minus]1] of data taken in the 1992--1993 run by the D0 detector at the Fermilab Tevatron collider; the cross sections were measured to be:[sigma][sub W][center-dot] Br(W[r-arrow] e[nu])= 2.36[+-] 0.02[+-] 0.07[+-] 0.13 nb and[sigma][sub Z][center-dot] Br(Z[r-arrow] ee)= 0.218[+-] 0.008[+-] 0.008[+-] 0.012 nb. The first error is statistical, the second error represents the non-luminosity systematic error, and the third error shows the uncertainty in the luminosity determination. Future prospects for similar measurements based on larger samples of data are discussed.




Measurement of Inclusive Jet Cross-sections in Z/gamma*( ---] E+ E- ) + Jets Production in P Anti-p Collisions at S**1/2


Book Description

Inclusive jet cross sections in Z/[gamma]* events, with Z/[gamma]* decaying into an electron-positron pair, are measured as a function of jet transverse momentum and jet multiplicity in p{bar p} collisions at √s - 1.96 TeV with the upgraded Collider Detector at Fermilab in Run II, based on an integrated luminosity of 1.7 fb−1. The measurements cover the rapidity region




Measurements of Inclusive W and Z Cross Sections in Pp Collisions at Sqrt(s)


Book Description

Measurements of inclusive W and Z boson production cross sections in pp collisions at sqrt(s)=7 TeV are presented, based on 2.9 inverse picobarns of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give sigma(pp to WX) times B(W to muon or electron + neutrino) = 9.95 \pm 0.07(stat.) \pm 0.28(syst.) \pm 1.09(lumi.) nb and sigma(pp to ZX) times B(Z to oppositely charged muon or electron pairs) = 0.931 \pm 0.026(stat.) \pm 0.023(syst.) \pm 0.102(lumi.) nb. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported.




Measurement of the Inclusive W and Z Production Cross Sections in Pp Collisions at $ \sqrt {s}


Book Description

A measurement of inclusive W and Z production cross sections in pp collisions at sqrt(s)=7 TeV is presented. The electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. The measured inclusive cross sections are sigma(pp-> WX) B(W-> l nu) = 10.30 +/- 0.02 (stat.) +/- 0.10 (syst.) +/- 0.10 (th.) +/- 0.41 (lumi.) nb and sigma(pp -> ZX) B(Z-> l+̂l-̂) = 0.974 +/- 0.007 (stat.) +/- 0.007 (syst.) +/- 0.018 (th.) +/- 0.039 (lumi.) nb, limited to the dilepton invariant mass range 60 to 120 GeV. The luminosity-independent cross section ratios are [sigma(pp->WX) B(W-> l nu)]/[sigma(pp-> ZX) B(Z->l+̂l-̂)] = 10.54 +/- 0.07 (stat.) +/- 0.08 (syst.) +/- 0.16 (th.) and [sigma(pp->W+̂X) B(W+̂ -> l+̂nu)] / [sigma(pp->W-̂ X) B(W-̂ -> l-̂ nu)] = 1.421 +/- 0.006 (stat.) +/- 0.014 (syst.) +/- 0.029 (th.). The measured values agree with next-to-next-to-leading order QCD cross section calculations based on recent parton distribution functions.










Measurement of Particle Production and Inclusive Differential Cross Sections in P Anti-p Collisions at S**1/2


Book Description

We report a set of measurements of particle production in inelastic p{bar p} collisions collected with a minimum-bias trigger at the Tevatron Collider with the CDF II experiment. The inclusive charged particle transverse momentum differential cross section is measured, with improved precision, over a range about ten times wider than in previous measurements. The former modeling of the spectrum appears to be incompatible with the high particle momenta observed. The dependence of the charged particle transverse momentum on the event particle multiplicity is analyzed to study the various components of hadron interactions. This is one of the observable variables most poorly reproduced by the available Monte Carlo generators. A first measurement of the event transverse energy sum differential cross section is also reported. A comparison with a PYTHIA prediction at the hadron level is performed. The inclusive charged particle differential production cross section is fairly well reproduced only in the transverse momentum range available from previous measurements. At higher momentum the agreement is poor. The transverse energy sum is poorly reproduced over the whole spectrum. The dependence of the charged particle transverse momentum on the particle multiplicity needs the introduction of more sophisticated particle production mechanisms, such as multiple parton interactions, in order to be better explained.