Measurement of the Υ (1S) Production Cross Section in Proton-Proton Collisions at Center of Mass Energy 7 TeV

Measurement of the Υ (1S) Production Cross Section in Proton-Proton Collisions at Center of Mass Energy 7 TeV PDF Author: Maxwell Ian Scherzer
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Measurement of the Υ (1S) Production Cross Section in Proton-Proton Collisions at Center of Mass Energy 7 TeV

Measurement of the Υ (1S) Production Cross Section in Proton-Proton Collisions at Center of Mass Energy 7 TeV PDF Author: Maxwell Ian Scherzer
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Measurement of the Upsilon(1S) Production Cross Section in Proton-Proton Collisions at Center of Mass Energy 7 TeV

Measurement of the Upsilon(1S) Production Cross Section in Proton-Proton Collisions at Center of Mass Energy 7 TeV PDF Author: Maxwell Ian Scherzer
Publisher:
ISBN:
Category :
Languages : en
Pages : 262

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A measurement of the cross section for upsilon(1S) production in proton-proton collisions at center of mass energy 7 TeV is presented. The measurement uses the upsilon(1S) 2!mu + mu decay mode and covers up to a transverse momentum of 26 GeV in two bins of rapidity; upsilon(1S) upsilon(1S) -1, collected with the ATLAS detector at the Large Hadron Collider. Templates derived from data are used to model the continuum background. In order to eliminate theoretical uncertainties due to the unknown polarization, the measurement is restricted to the case where both muons have a transverse momentum of p mu T> 4 GeV and a pseudorapidit

First Measurement of the Top-quark Pair Production Cross Section in Proton-proton Collisions at the Center of Mass Energy of 7 TeV

First Measurement of the Top-quark Pair Production Cross Section in Proton-proton Collisions at the Center of Mass Energy of 7 TeV PDF Author: Puneeth D. Kalavase
Publisher:
ISBN: 9781124885476
Category :
Languages : en
Pages : 167

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The first measurement of the cross section for top-quark pair production in proton-proton collisions at the Large Hadron Collider at center-of-mass energy of 7 TeV has been performed using a data sample corresponding to an integrated luminosity of 3 pb-1 recorded by the CMS detector. This result utilizes the final state with two isolated, highly energetic charged leptons, large missing transverse energy, and two or more jets. Backgrounds from Drell-Yan and non-W/Z boson production are estimated from data. Eleven events are observed in the data with 2.1+/-1.0 events expected from background. The measured cross section is 194+/-72 (statistical) +/-24 (systematic) +/-21 (luminosity) pb. The result is consistent with next-to-leading order theoretical predictions.

First Measurement of the Cross Section for Top-Quark Pair Production in Proton-Proton Collisions at $\sqrt{s}

First Measurement of the Cross Section for Top-Quark Pair Production in Proton-Proton Collisions at $\sqrt{s} PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 26

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The first measurement of the cross section for top-quark pair production in pp collisions at the LHC at center-of-mass energy sqrt(s)= 7 TeV has been performed using 3.1 {\pm} 0.3 inverse pb of data recorded by the CMS detector. This result utilizes the final state with two isolated, highly energetic charged leptons, large missing transverse energy, and two or more jets. Backgrounds from Drell-Yan and non-W/Z boson production are estimated from data. Eleven events are observed in the data with 2.1 {\pm} 1.0 events expected from background. The measured cross section is 194 {\pm} 72 (stat.) {\pm} 24 (syst.) {\pm} 21 (lumi.) pb, consistent with next-to-leading order predictions.

Measurement of the Inclusive $Z \to Ee$ Production Cross Section in Proton-Proton Collisions at $\sqrt{s}$

Measurement of the Inclusive $Z \to Ee$ Production Cross Section in Proton-Proton Collisions at $\sqrt{s}$ PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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This thesis comprises a precision measurement of the inclusive \Zee production cross section in proton-proton collisions provided by the Large Hadron Collider (LHC) at a center-of-mass energy of $\sqrt{s}=7$~TeV and the absolute luminosity based on \Zee decays. The data was collected by the Compact Muon Solenoid (CMS) detector near Geneva, Switzerland during the year of 2010 and corresponds to an integrated luminosity of $\int\mathcal{L}dt = 35.9\pm 1.4$~pb$^{-1}$. Electronic decays of $Z$ bosons allow one of the first electroweak measurements at the LHC, making the cross section measurement a benchmark of physics performance after the first year of CMS detector and LHC machine operations. It is the first systematic uncertainty limited \Zee cross section measurement performed at $\sqrt{s}=7$~TeV. The measured cross section pertaining to the invariant mass window $M_{ee}\in (60,120)$~GeV is reported as: $\sigma(pp\to Z+X) \times \mathcal{B}(Z\to ee) = 997 \pm 11 \mathrm{(sta t)} \pm 19 \mathrm{(syst)} \pm 40 \mathrm{(lumi)} \textrm{ pb}$, which agrees with the theoretical prediction calculated to NNLO in QCD. Leveraging \Zee decays as ``standard candles'' for measuring the absolute luminosity at the LHC is examined; they are produced copiously, are well understood, and have clean detector signatures. Thus the consistency of the inclusive \Zee production cross section measurement with the theoretical prediction motivates inverting the measurement to instead use the \Zee signal yield to measure the luminosity. The result, which agrees with the primary relative CMS luminosity measurement calibrated using Van der Meer separation scans, is not only the most precise absolute luminosity measurement performed to date at a hadron collider, but also the first one based on a physics signal at the LHC.

Measurement of the Production Cross-section of Two W Bosons from Seven-trillion-electronvolt Center-of-mass-energy Proton-proton Collisions

Measurement of the Production Cross-section of Two W Bosons from Seven-trillion-electronvolt Center-of-mass-energy Proton-proton Collisions PDF Author: Jacob Thomas Ribnik
Publisher:
ISBN: 9781124885773
Category :
Languages : en
Pages : 177

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This dissertation describes the first WW production cross-section measurement in 35.5 pb-1 of s = 7 TeV pp collision data recorded by the CMS detector. The ee, emu and mumu final states are considered. The event yields, expectations and systematic uncertainties arc presented, and the data-driven methods used to estimate the background and selection efficiency are discussed in detail. The cross-section is measured to be sigmaWW = 41.1 +/- 15.3(stat.) +/- 5.8(syst.) +/- 4.5(lumi.) pb. The same data is used to place constraints on anomalous WWgamma and WWZ couplings.

Measurement of the WW Production Cross-section in Proton-Proton Collisions at √s

Measurement of the WW Production Cross-section in Proton-Proton Collisions at √s PDF Author: Jun Gao
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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The Standard Model (SM), actual fundamental theory for particle physics, provides a description of the elementary particles and the fundamental interactions: the electromagnetic, weak and strong forces. At the European Organization for Nuclear Research (CERN), physicists and engineers from all over the world are searching to understand the fundamental laws of the universe. It is at CERN that the world's largest and most sophisticated experimental instruments have been built, to accelerate particles at the energy of 3.5-4 TeV with the Large Hadron Collider (LHC). A Toroidal LHC ApparatuS (ATLAS), one of the four main detectors at LHC. In ATLAS, di-boson production is one of the most important electro-weak processes.The electro-weak sector of the SM, as well as the strong interactions, can be tested through the precision measurements of the W+W− production cross section. A measurement of the W+W− production cross section in 8 TeV center of mass proton-proton collisions is presented here from data collected with the ATLAS detector at the LHC for a total integrated luminosity of 20.3 fb−1. The W+W− events are selected with 3 final states: ee, eμ, and μμ. In order to suppress the background contamination, mainly from the Drell-Yan and ttbar processes, a cut on missing transverse energy is applied and events with hadronic jets satisfying appropriate selection criteria are rejected. The major backgrounds, mainly including W +jets, top and Z+jets, are estimated by data driven technique. The measured cross section is 71.0+1⋅1−1⋅1(stat)+5⋅7−5⋅0(syst)+2⋅1−2⋅0(lumi) pb, which is consistent with SM Next-to-Next-Leading-Order prediction of 63.2+2⋅0−1⋅8 pb.

Measurement of Dijet Cross Sections in Proton-proton Collisions at 7 TeV Center-of-mass Energy Using the ATLAS Detector

Measurement of Dijet Cross Sections in Proton-proton Collisions at 7 TeV Center-of-mass Energy Using the ATLAS Detector PDF Author:
Publisher:
ISBN: 9781303634567
Category :
Languages : en
Pages : 141

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Book Description
Dijet production is measured in proton--proton collisions with a center-of-mass energy of 7 TeV at the LHC. Double-differential dijet cross sections are presented as functions of the dijet mass and rapidity separation of the two highest-transverse-momentum jets in an event. The data sample collected in 2011 by the ATLAS detector is considered, corresponding to an integrated luminosity of 4.5 fb -1. Jets are defined using the anti-kt algorithm, with two choices of the jet radius parameter, R = 0.4 and R = 0.6. The results are compared with next-to-leading-order (NLO) perturbative calculations, as well as NLO Monte Carlo generator predictions. In both cases, electroweak effects are accounted for. A method for the quantitative comparison of theory predictions with data is presented, employing a frequentist technique. This allows for strong statements on which sets of parton distribution functions best describe the data. A theory of quark compositeness modeled by contact interactions is confronted by the unfolded data using the CLs technique, an example of the versatility of the measurement.

Measurement of the Top Quark Pair Production Cross Section in Pp Collisions at a Center-of-mass Energy of 7 TeV with the CMS Experiment at the LHC

Measurement of the Top Quark Pair Production Cross Section in Pp Collisions at a Center-of-mass Energy of 7 TeV with the CMS Experiment at the LHC PDF Author: Geng-Yuan Jeng
Publisher:
ISBN:
Category : Large Hadron Collider (France and Switzerland)
Languages : en
Pages : 140

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Book Description
We perform a measurement of the top quark pair production cross section in pp collisions at a center-of-mass energy of 7 TeV at the Large Hadron Collider. The analysis is based on a 36 pb -1 dataset collected with the CMS experiment in 2010. We study the kinematic characteristics of events with exactly one isolated muon in association with additional hard jets and exhibiting substantial missing transverse energy to distinguish the tt− signal from the electroweak and QCD multijet backgrounds. The tt− signal is extracted by simultaneously fitting the tri-jet invariant mass distributions in events with exactly three jets and at least four jets. The measured cross section is 157 ± 12(stat.[Special characters omitted.] (syst.) ± 6(lumi.) pb, which is consistent with the theoretical predictions.

Measurement of the Inclusive Electron Cross-Section from Heavy-Flavour Decays and Search for Compressed Supersymmetric Scenarios with the ATLAS Experiment

Measurement of the Inclusive Electron Cross-Section from Heavy-Flavour Decays and Search for Compressed Supersymmetric Scenarios with the ATLAS Experiment PDF Author: Moritz Backes
Publisher: Springer
ISBN: 331907136X
Category : Science
Languages : en
Pages : 268

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Book Description
The first part of this thesis presents the measurement of the inclusive cross-section for electron production from heavy-flavour decays in the electron transverse momentum range 7 GeV