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} PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 151

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Book Description
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

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} PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 151

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Book Description
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

Measurement of Z/γ*+b—jet Production Cross Section in Pp Collisions at √s

Measurement of Z/γ*+b—jet Production Cross Section in Pp Collisions at √s PDF Author: Lorenzo Ortolan
Publisher:
ISBN: 9788449031298
Category :
Languages : en
Pages : 145

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Book Description


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) PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 39

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Book Description
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 W-gamma and Z-gamma Production in Pp Collisions at Sqrt(s)

Measurement of W-gamma and Z-gamma Production in Pp Collisions at Sqrt(s) PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 32

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Book Description
A measurement of W-gamma and Z-gamma production in proton-proton collisions at sqrt(s) = 7 TeV is presented. Results are based on a data sample recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 36 inverse picobarns. The electron and muon decay channels of the W and Z are used. The total cross sections are measured for photon transverse energy>10 GeV and spatial separation from charged leptons in the plane of pseudorapidity and azimuthal angle>0.7, and with an additional dilepton invariant mass requirement of> 50 GeV for the Z-gamma process. The following cross section times branching fraction values are found: sigma(pp to W-gamma+X) B(W to lepton neutrino) = 56.3 +/- 5.0 (stat.) +/- 5.0 (syst.) +/- 2.3 (lumi.) pb and sigma(pp to Z-gamma+X) B}(Z to lepton lepton) = 9.4 +/- 1.0 (stat.) +/- 0.6 (syst.) +/- 0.4 (lumi.) pb. These measurements are in agreement with standard model predictions. The first limits on anomalous WW gamma, ZZ gamma, and Z gamma gamma trilinear gauge couplings at sqrt(s) = 7 TeV are set.

Measurement of Cross Sections for B Jet Production in Events with a Z Boson in P-anti-p Collisions at S**1/2

Measurement of Cross Sections for B Jet Production in Events with a Z Boson in P-anti-p Collisions at S**1/2 PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 31

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Book Description
A measurement of the b jet production cross section is presented for events containing a Z boson produced in p{bar p} collisions at √s = 1.96 TeV, using data corresponding to an integrated luminosity of 2 fb−1 collected by the CDF II detector at the Tevatron. Z bosons are selected in the electron and muon decay modes. Jets are considered with transverse energy E{sub T} > 20 GeV and pseudorapidity.

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 PDF Author: Rodger Mantifel
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
"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." --

Measurement of the $ \mathrm{ Z } \gamma \rightarrow \nu \bar{\nu} \gamma$ Production Cross Section in Pp Collisions at $\sqrt{s}

Measurement of the $ \mathrm{ Z } \gamma \rightarrow \nu \bar{\nu} \gamma$ Production Cross Section in Pp Collisions at $\sqrt{s} PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
A measurement of the Z gamma to nu nu-bar gamma production cross section in pp collisions at sqrt(s) = 8 TeV is presented, using data corresponding to an integrated luminosity of 19.6 inverse-femtobarns collected with the CMS detector at the LHC. This measurement is based on the observation of events with large missing energy and with a single photon with transverse momentum above 145 GeV and absolute pseudorapidity in the range

Measurement of the B Jet Cross-section in Events with a Z Boson in P Anti-p Collisions at S**1/2

Measurement of the B Jet Cross-section in Events with a Z Boson in P Anti-p Collisions at S**1/2 PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 28

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Book Description


Inclusive B-jet Production in Pp Collisions at Sqrt(s)

Inclusive B-jet Production in Pp Collisions at Sqrt(s) PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 33

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Book Description
The inclusive b-jet production cross section in pp collisions at a center-of-mass energy of 7 TeV is measured using data collected by the CMS experiment at the LHC. The cross section is presented as a function of the jet transverse momentum in the range 18

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 PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 7

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Book Description
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