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

Measurement of Inclusive Jet Cross-sections in Z/gamma*( ---] E+ E- ) + Jets Production in P Anti-p Collisions at S**1/2
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Total Pages: 7
Release: 2007
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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

Measurement of Inclusive Jet Cross Sections in Z/gamma*( -]e+e- ) + Jets Production in Ppbar Collisions at S**1/2

Measurement of Inclusive Jet Cross Sections in Z/gamma*( -]e+e- ) + Jets Production in Ppbar Collisions at S**1/2
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Total Pages: 144
Release: 2008
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This Ph. D. thesis presents the measurement of inclusive jet cross sections in Z/[gamma]* 2!ee− events using 1.7 fb−1 of data collected by the upgraded CDF detector during the Run II of the Tevatron. The Midpoint cone algorithm is used to search for jets in the events after identifying the presence of a Z/[gamma]* boson through the reconstruction of its decay products. The measurements are compared to next-to-LO (NLO) pQCD predictions for events with one and two jets in the final state. The perturbative predictions are corrected for the contributions of non-perturbative processes, like the underlying event and the fragmentation of the partons into jets of hadrons. These processes are not described by perturbation theory and must be estimated from phenomenological models. In this thesis, a number of measurements are performed to test different models of underlying event and hadronization implemented in LO plus parton shower Monte Carlo generator programs. Chapter 2 is devoted to the description of the theory of strong interactions and jet phenomenology at hadron colliders. Chapter 3 contains the description of the Tevatron collider and the CDF detector. The analysis is described in detail in Chapter 4. Chapter 5 shows the measurement of those observables sensitive to non-perturbative effects compared to the predictions from several Monte Carlo programs. Chapter 6 discusses the final results and the comparison with theoretical expectations. Finally, Chapter 7 is devoted to the conclusions.

Measurement of Inclusive Jet Cross Sections in Z/?*({u2192}e+e-) + Jets Production in P$\bar{p}$ Collisions at {u221A}s

Measurement of Inclusive Jet Cross Sections in Z/?*({u2192}e+e-) + Jets Production in P$\bar{p}$ Collisions at {u221A}s
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Total Pages: 144
Release: 2008
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This Ph.D. thesis presents the measurement of inclusive jet cross sections in Z/?*→ e+e- events using 1.7 fb-1 of data collected by the upgraded CDF detector during the Run II of the Tevatron. The Midpoint cone algorithm is used to search for jets in the events after identifying the presence of a Z/?* boson through the reconstruction of its decay products. The measurements are compared to next-to-LO (NLO) pQCD predictions for events with one and two jets in the final state. The perturbative predictions are corrected for the contributions of non-perturbative processes, like the underlying event and the fragmentation of the partons into jets of hadrons. These processes are not described by perturbation theory and must be estimated from phenomenological models. In this thesis, a number of measurements are performed to test different models of underlying event and hadronization implemented in LO plus parton shower Monte Carlo generator programs. Chapter 2 is devoted to the description of the theory of strong interactions and jet phenomenology at hadron colliders. Chapter 3 contains the description of the Tevatron collider and the CDF detector. The analysis is described in detail in Chapter 4. Chapter 5 shows the measurement of those observables sensitive to non-perturbative effects compared to the predictions from several Monte Carlo programs. Chapter 6 discusses the final results and the comparison with theoretical expectations. Finally, Chapter 7 is devoted to the conclusions.

Measurements of Jet Multiplicity and Differential Production Cross Sections of Z + Jets Events in Proton-proton Collisions at {u221A}s

Measurements of Jet Multiplicity and Differential Production Cross Sections of Z + Jets Events in Proton-proton Collisions at {u221A}s
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Release: 2015
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Measurements of differential cross sections are presented for the production of a Z boson and at least one hadronic jet in proton-proton collisions at √s = 7 TeV, recorded by the CMS detector, using a data sample corresponding to an integrated luminosity of 4.9 inverse femtobarns. The jet multiplicity distribution is measured for up to six jets. The differential cross sections are measured as a function of jet transverse momentum and pseudorapidity for the four highest transverse momentum jets. The distribution of the scalar sum of jet transverse momenta is also measured as a function of the jet multiplicity. The measurements are compared with theoretical predictions at leading and next-to-leading order in perturbative QCD.

Measurement of the Production Cross Sections for a Z Boson and One Or More B Jets in Pp Collisions at Sqrt(s)

Measurement of the Production Cross Sections for a Z Boson and One Or More B Jets in Pp Collisions at Sqrt(s)
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Total Pages: 39
Release: 2014
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The production of a Z boson, decaying into two leptons and produced in association with one or more b jets, is studied using proton-proton collisions delivered by the LHC at a centre-of-mass energy of 7 TeV. The data were recorded in 2011 with the CMS detector and correspond to an integrated luminosity of 5 fb-1. The Z(ll) + b-jets cross sections (where ll = [mu][mu] or ee) are measured separately for a Z boson produced with exactly one b jet and with at least two b jets. In addition, a cross section ratio is extracted for a Z boson produced with at least one b jet, relative to a Z boson produced with at least one jet. The measured cross sections are compared to various theoretical predictions, and the data favour the predictions in the five-flavour scheme, where b quarks are assumed massless. The kinematic properties of the reconstructed particles are compared with the predictions from the MadGraph event generator using the pythia parton shower simulation.

Measurement of the Inclusive Jet Cross Section in Pp Collisions at Sqrt[s]

Measurement of the Inclusive Jet Cross Section in Pp Collisions at Sqrt[s]
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Release: 2011
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The inclusive jet cross section is measured in pp collisions with a center-of-mass energy of 7 TeV at the LHC using the CMS experiment. The data sample corresponds to an integrated luminosity of 34 inverse picobarns. The measurement is made for jet transverse momenta in the range 18-1100 GeV and for absolute values of rapidity less than 3. The measured cross section extends to the highest values of jet pT ever observed and, within the experimental and theoretical uncertainties, is generally in agreement with next-to-leading-order perturbative QCD predictions.

Measurement of the Ratio of Inclusive Cross Sections!(p-p!Z+b-jet)!(p-p!Z+jet) in the Dilepton Final States

Measurement of the Ratio of Inclusive Cross Sections!(p-p!Z+b-jet)!(p-p!Z+jet) in the Dilepton Final States
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Total Pages: 190
Release: 2010
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The inclusive production of b-jets with a Z boson is an important background to searches for the Higgs boson in associated ZH → llb{bar b} production at the Fermilab Tevatron collider. This thesis describes the most precise measurement to date of the ratio of inclusive cross sections [sigma](p{bar p} → Z + b-jet)/[sigma](p{bar p} → Z + jet) when a Z boson decays into two electrons or muons. The measurement uses a data sample from p{bar p} collisions at the center of mass energy √s = 1.96 TeV corresponding to an integrated luminosity of 4.2 fb−1 collected by the D0 detector. The measured ratio [sigma](Z + b-jet)/[sigma](Z + jet) is 0.0187 ± 0.0021(stat) ± 0.0015(syst) for jets with transverse momentum p{sub T} > 20 GeV and pseudorapidity.