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

Measurements of Differential Cross Sections of Z/gamma*+jets+X Events in Proton Anti-proton Collisions at S**ư
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Total Pages: 11
Release: 2009
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We present cross section measurements for Z/?* + 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.

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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Total Pages: 11
Release: 2009
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ISBN:

Download Measurements of Differential Cross Sections of Z/gamma*+jets+X Events in Proton Anti-proton Collisions at S**1/2 Book in PDF, Epub and Kindle

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.

Measurements of Differential Z/gamma*+jet+X Cross Sections with the D0 Detector

Measurements of Differential Z/gamma*+jet+X Cross Sections with the D0 Detector
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Total Pages: 6
Release: 2009
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We present measurements of differential cross sections in inclusive Z/[gamma]* plus jet production in a data sample of 1 fb−1 collected with the D0 detector in proton antiproton collisions at √s = 1.96 TeV. Measured variables include the Z/[gamma]* transverse momentum (p{sub T}{sup Z}) and rapidity (y{sup Z}), the leading jet transverse momentum (p{sub T}{sup jet}) and rapidity (y{sup jet}), as well as various angles of the Z+jet system. We compare the results to different Monte Carlo event generators and next-to-leading order perturbative QCD (NLO pQCD) predictions, with non-perturbative corrections applied.

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.

Measurements of the Differential Production Cross Sections for a Z Boson in Association with Jets in Pp Collisions at $\sqrt{s}$

Measurements of the Differential Production Cross Sections for a Z Boson in Association with Jets in Pp Collisions at $\sqrt{s}$
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Release: 2016
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Cross sections for the production of a Z boson in association with jets in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$=8 TeV are measured using a data sample collected by the CMS experiment at the LHC corresponding to 19.6 inverse femtobarns. Differential cross sections are presented as functions of up to three observables that describe the jet kinematics and the jet activity. Correlations between the azimuthal directions and the rapidities of the jets and the Z boson are studied in detail. The predictions of a number of multileg generators with leading or next-to-leading order accuracy are compared with the measurements. The comparison shows the importance of including multi-parton contributions in the matrix elements and the improvement in the predictions when next-to-leading order terms are included.

Measurements of the Differential Cross Sections for the Inclusive Production of a Photon and Heavy Flavor Jet

Measurements of the Differential Cross Sections for the Inclusive Production of a Photon and Heavy Flavor Jet
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Total Pages: 168
Release: 2009
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This thesis presents the first measurement of the differential production cross section of a heavy flavor (bottom or charm) jet and direct photon at the Fermilab Tevatron. These measurements were performed using data recorded with the D0 detector from proton-antiproton collisions at a center of mass energy of √s = 1.96 TeV. These results probe a kinematic range for the photon transverse momentum of 30

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.