A Measurement of the Inclusive Z / gamma* --> mu+ mu- Cross-Section and Study of W and Z Events in proton - anti-proton Collisions at D0 (open access)

A Measurement of the Inclusive Z / gamma* --> mu+ mu- Cross-Section and Study of W and Z Events in proton - anti-proton Collisions at D0

A measurement of the inclusive Z/{gamma}* {yields} {mu}{sup +}{mu}{sup -} cross section for M{sub {mu}{mu}} > 40 GeV at {radical}s = 1.96 TeV is presented. The measurement is performed using a data sample corresponding to an integrated luminosity of 147.7 pb{sup -1}, collected with the D0 detector at the Tevatron, Fermilab, between September 2002 and October 2003. A total of 14352 di-muon events are selected and a final result of {sigma}(Z/{gamma}*) = 327.8 {+-} 3.4(stat.) {+-} 8.4(syst.) {+-} 21.3(lumi.) pb is obtained. Correcting the number of di-muon events by a factor of 0.885 {+-} 0.015 for the contribution from pure {gamma}* exchange and Z/{gamma}* interference, the inclusive Z {yields} {mu}{sup +}{mu}{sup -} cross section is found to be: {sigma}(Z) = 290.1 {+-} 3.0(stat.) {+-} 7.4(syst.) {+-} 18.9(lumi.) pb. Finally, comparisons of W and Z boson p{sub T} distributions as measured with D0 during Run I of the Tevatron are compared to HERWIG and MC{at}NLO predictions. Relevant parameters in the simulations are tuned to obtain the best possible fit to the data. An excellent agreement is found for both HERWIG and MC{at}NLO.
Date: February 1, 2005
Creator: Nurse, Emily L.
System: The UNT Digital Library
Measurement of the Ratio of Inclusive Cross Sections Sigma (p anti-p --> Z + b-jet) / Sigma (p anti-p --> Z + jet) at s**(1/2) = 1.96-TeV (open access)

Measurement of the Ratio of Inclusive Cross Sections Sigma (p anti-p --> Z + b-jet) / Sigma (p anti-p --> Z + jet) at s**(1/2) = 1.96-TeV

Using the data collected with the D0 detector at {radical}s = 1.96 TeV with integrated luminosities of about 180 pb{sup -1}, we have measured the ratio of inclusive cross sections for p{bar p} {yields} Z + b-jet to p{bar p} {yields} Z + jet production. The inclusive Z + b-jet reaction is an important background to searches for the Higgs boson in associated ZH production at the Fermilab Tevatron collider and is sensitive to the b quark content of the proton. This thesis describes our measurement which is performed using the dimuon decay channel of the Z boson, i.e. Z {yields} {mu}{sup +}{mu}{sup -}. The ratio in the dimuon channel is measured to be 1.86 {+-} 0.44(stat){sub -0.28}{sup +0.24}(syst)% for hadronic jets with transverse momenta p{sub T} > 20 GeV/c and pseudorapidities |{eta}| < 2.5, consistent with next-to-leading order predictions of the standard model. This measurement is also combined with the result of the same ratio using the dielectron decay of the Z boson, and the combined measurement of the ratio of cross-sections yields 2.11 {+-} 0.41(stat){sub -0.25}{sup +0.22}(syst)%. In addition to our measurement, we also study optimization procedures for the search of Z({mu} {bar {mu}})+b{bar b} signal at D0. …
Date: February 1, 2005
Creator: Mutaf, Yildirim D.
System: The UNT Digital Library
Measurement of the top - anti-top Production Cross Section at s**(/1/2) = 1.96-TeV in the e + jets Final State of proton anti-proton Collisions at the Tevatron (open access)

Measurement of the top - anti-top Production Cross Section at s**(/1/2) = 1.96-TeV in the e + jets Final State of proton anti-proton Collisions at the Tevatron

We discuss the measurement of the cross section for t{bar t} production in p{bar p} collisions at {radical}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{sup +} {nu}{sub e} or e{sup -} {bar {nu}}{sub 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 …
Date: February 1, 2005
Creator: Cho, DooKee
System: The UNT Digital Library
An Analytic Tool to Investigate the Effect of Binder on the Sensitivity of HMX-Based Plastic Bonded Explosives in the Skid Test (open access)

An Analytic Tool to Investigate the Effect of Binder on the Sensitivity of HMX-Based Plastic Bonded Explosives in the Skid Test

This project will develop an analytical tool to calculate performance of HMX based PBXs in the skid test. The skid-test is used as a means to measure sensitivity for large charges in handling situations. Each series of skid tests requires dozens of drops of large billets. It is proposed that the reaction (or lack of one) of PBXs in the skid test is governed by the mechanical properties of the binder. If true, one might be able to develop an analytical tool to estimate skid test behavior for new PBX formulations. Others over the past 50 years have tried to develop similar models. This project will research and summarize the works of others and couple the work of 3 into an analytical tool that can be run on a PC to calculate drop height of HMX based PBXs. Detonation due to dropping a billet is argued to be a dynamic thermal event. To avoid detonation, the heat created due to friction at impact, must be conducted into the charge or the target faster than the chemical kinetics can create additional energy. The methodology will involve numerically solving the Frank-Kamenetskii equation in one dimension. The analytical problem needs to be bounded …
Date: February 1, 2005
Creator: Hayden, D. W.
System: The UNT Digital Library