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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Published: 2008

Total Pages: 144

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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/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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Published: 2007

Total Pages: 7

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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/?*({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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Published: 2008

Total Pages: 144

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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.

Measurement of the Inclusive Jet Cross Section Using the K(T) Algorithm in P Anti-p Collisions at S**1/2
Measurement of the Inclusive Jet Cross Section Using the K(T) Algorithm in P Anti-p Collisions at S**1/2

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Published: 2005

Total Pages: 13

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The authors report on a measurement of the inclusive jet production cross section in p{bar p} collisions at √s = 1.96 TeV using data collected with the upgraded Collider Detector at Fermilab in Run II (CDF II) corresponding to an integrated luminosity of 385 pb−1. Jets are reconstructed using the k{sub T} algorithm. The measurement is carried out for jets with rapidity 0.1

Z + Jets Cross Section Ratio Measurements
Z + Jets Cross Section Ratio Measurements

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Published: 2007

Total Pages: 4

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We present a study of events with Z bosons and jets produced at the Fermilab Tevatron Collider in p{bar p} collisions at a center of mass energy of 1.96 TeV. The data sample consists of nearly 14,000 Z/[gamma]* 2!ee− candidates corresponding to the integrated luminosity of 340 pb−1 collected using the D0 detector. Ratios of the Z/[gamma]* + d"n jet cross sections to the total inclusive Z/[gamma]* cross section have been measured for n = 1 to 4 jet events. Our measurements are found to be in good agreement with a next-to-leading order QCD calculation and with a tree-level QCD prediction with parton shower simulation and hadronization.

Measurements of Differential Cross Sections of Z/gamma*+jets+X Events in Proton Anti-proton Collisions at S**1/2
Measurements of Differential Cross Sections of Z/gamma*+jets+X Events in Proton Anti-proton Collisions at S**1/2

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Published: 2009

Total Pages: 11

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We present cross section measurements for Z/[gamma]* + jets + X production, differential in the transverse momenta of the three leading jets. The data sample was collected with the D0 detector at the Fermilab Tevatron p{bar p} collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of 1 fb−1. Leading and next-to-leading order perturbative QCD predictions are compared with the measurements, and agreement is found within the theoretical and experimental uncertainties. We also make comparisons with the predictions of four event generators. Two parton-shower-based generators show significant shape and normalization differences with respect to the data. In contrast, two generators combining tree-level matrix elements with a parton shower give a reasonable description of the shapes observed in data, but the predicted normalizations show significant differences with respect to the data, reflecting large scale uncertainties. For specific choices of scales, the normalizations for either generator can be made to agree with the measurements.

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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Published: 2010

Total Pages: 190

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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.

Measurement of $Z/\gamma^* + B$-jet Production Cross Section in $p\bar{p}$ Collisions at $\sqrt{s}
Measurement of $Z/\gamma^* + B$-jet Production Cross Section in $p\bar{p}$ Collisions at $\sqrt{s}

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Published: 2012

Total Pages: 151

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Processes at hadron colliders, such as the production of jets, are described by the Quantum Chromodynamics theory (QCD). Precise descriptions of processes involving jets in association with a vector boson have nowadays large relevance as they represent irreducible background to other Standard Model (SM) processes and searches for new physics. The experimental study and understanding of the b-jet production in association with a Z boson are crucial for many reasons. For one side, it is the most important background for a light Higgs boson decaying into a bottom-antibottom quark pair and produced in the ZH mode. This is one of the most promising channels for the Higgs search at Tevatron in particular since the latest results have excluded the high mass region (MH> 127 GeV/c2). For another side the signature of b-jets and a Z boson is also background to new physics searches, such as supersymmetry, where a large coupling of the Higgs boson to bottom quarks is allowed. The produ ction cross section measurement of b-jets in events with a Z boson has already been performed at hadron colliders, at the Tevatron by CDF and D0 experiments and are now pursued at the LHC by ATLAS and CMS. In particular the CDF measurement was performed with only 2 fb-1 and was limited by the statistical uncertainty. This PhD thesis presents a new measurement of the $Z/\gamma^* + b$-jet production cross section using the complete dataset collected by CDF during the Run II. $Z/\gamma^*$ bosons are selected in the electron and muon decay modes and are required to have 66

Inclusive Jet Cross Section at CDF
Inclusive Jet Cross Section at CDF

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Published: 2005

Total Pages: 4

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This contribution reports on preliminary measurements of the inclusive jet production cross section in p{bar p} collisions at √s = 1.96 TeV using data collected with CDF corresponding to an integrated luminosity of 385 pb−1. Two analyzes are presented: one uses the longitudinally invariant k{sub T} algorithm to reconstruct the jets, the other uses the midpoint algorithm. Both are limited to jets with rapidity in the range 0.1