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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Published: 2009

Total Pages: 11

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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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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.

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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Published: 2009

Total Pages: 6

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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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Published: 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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Published: 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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Published: 2009

Total Pages: 168

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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 the Production Cross Section of Jets in Association with a Z Boson in 8 TeV Proton-proton Collisions with the ATLAS Detector
Measurement of the Production Cross Section of Jets in Association with a Z Boson in 8 TeV Proton-proton Collisions with the ATLAS Detector

Author: Rodger Mantifel

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Published: 2017

Total Pages:

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"This thesis presents the measurement of the production cross sections of jets in association with a Z boson in proton-proton collisions at √s = 8 TeV with an integrated luminosity of 20.3 fb−1 recorded by the ATLAS experiment at the Large Hadron Collider at CERN. Inclusive and differential Z/[gamma]∗(→ e+e−)+jets cross sections are measured for jets with a transversemomentum pT(jet) > 30 GeV and rapidity |y(jet)| 4.4. Z boson candidates are identified by their decay into electron pairs. In order to stringently probe the modelling of Z/[gamma]∗+jets production by Monte Carlo generators in regions of high-pT phase space typical for Higgs boson decay and searches for new physics, events with high-pT final states are investigated. High-pT final states are defined as events with either pT(Z) 300 GeV or pT(leading jet) > 300 GeV. A set of four observables, sensitive to the topology of the event, are measured for the standard event selection as well as in the regions of high-pT phase space. The results from data are unfolded to particle level and compared to calculations of the matrix element from Monte Carlo generators Alpgen+Pythia and Sherpa interfaced to a parton shower. The results show that Sherpa tends to model Z/[gamma]∗+jets production in high-pT regions of phase space much better than Alpgen+Pythia." --

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

Author: Daniel J. Duggan

Publisher:

Published: 2009

Total Pages:

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ABSTRACT: 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 sqrt(s) = 1.96 TeV. These results probe a kinematic range for the photon transverse momentum of 30 to 150 GeV and photon rapidity y