Author: Albert M. SirunyanPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Measurements of Production Cross Sections of Polarized Same-sign W Boson Pairs in Association with Two Jets in Proton-proton Collisions at √s
Author: Albert M. SirunyanMeasurements of Production Cross Sections of WZ and Same-sign WW Boson Pairs in Association with Two Jets in Proton-proton Collisions at √s
Author: Albert M. SirunyanA Measurement of W Boson Pair Production in Pp Collisions at Sqrt(s)
Author: Philip SommerPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Zusammenfassung: In this thesis, measurements of the W boson pair production cross section in proton-proton collisions at a centre-of-mass energy of 8 TeV are presented. A dataset corresponding to an integrated luminosity of 22.3 /fb recorded by the ATLAS experiment in the year 2012 is used. The W bosons are identified by their decay products of exactly two leptons with opposite electrical charge, electrons or muons, and missing transverse momentum induced by their corresponding neutrinos. First, a measurement restricted to final states without hadronic jets is presented and differential fiducial cross sections, total cross sections and limits on anomalous triple gauge boson couplings are obtained. A second measurement of the fiducial cross section in association with exactly one hadronic jet is presented. The ratio of fiducial cross sections for different jet multiplicities is reported and the combined fiducial cross section is extrapolated to the total phase space.
Measurement of the Production Cross Section for a W Boson and Two B Jets in Pp Collisions at $\sqrt{s}$
Author: Measurement of the Production Cross Section of the W Boson in Association with Two B Jets in Pp Collisions at $\sqrt{s}$
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The production cross section of a W boson in association with two b jets is measured using a sample of proton-proton collisions at $ \sqrt{s} = $ 8 TeV collected by the CMS experiment at the CERN LHC. The data sample corresponds to an integrated luminosity of 19.8 fb$^{-1}$. The W bosons are reconstructed via their leptonic decays, $ \mathrm{ W }\to\ell\nu $, where $\ell=\mu$ or $\mathrm{ e }$. The fiducial region studied contains exactly one lepton with transverse momentum $ p_{\mathrm{T}}^{\ell}> $ 30 GeV and pseudorapidity $
Measurements of Differential Cross Sections for Associated Production of a W Boson and Jets in Proton-proton Collisions at $\sqrt{s}$
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Differential cross sections for a W boson produced in association with jets are measured in a data sample of proton-proton collisions at a center-of-mass energy of 8 TeV recorded with the CMS detector and corresponding to an integrated luminosity of 19.6 inverse femtobarns. The W bosons are identified through their decay mode W to mu nu. The cross sections are reported as functions of jet multiplicity, transverse momenta, and the scalar sum of jet transverse momenta (HT) for different jet multiplicities. Distributions of the angular correlations between the jets and the muon are examined, as well as the average number of jets as a function of HT and as a function of angular variables. The measured differential cross sections are compared with tree-level and higher-order recent event generators, as well as next-to-leading-order and next-to-next-to-leading-order theoretical predictions. The agreement of the generators with the measurements builds confidence in their use for the simulation of W+jets background processes in searches for new physics at the LHC.
Differential Cross Section Measurements for the Production of a W Boson in Association with Jets in Proton{u2013}proton Collisions at {u221A}s
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 26
Book Description
Our measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. Furthermore, the data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb-1. The measured cross sections are compared to predictions from Monte Carlo generators, MADGRAPH + PYTHIAand SHERPA, and to next-to-leading-order calculations from BLACKHAT + SHERPA. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.
Spin Correlations in tt Events from pp Collisions
Author: Boris LemmerPublisher: Springer
ISBN: 3319189328
Category : Science
Languages : en
Pages : 246
Book Description
This thesis introduces readers to the Standard Model, the top quark and its properties, before explaining the concept of spin correlation measurement. The first measurement of top quark spin correlations at the LHC in the lepton+jets decay channel is presented. As the heaviest elementary particle, the top quark plays an essential role in the Standard Model of elementary particle physics. In the case of top quarks being produced in pairs at hadron colliders, the Standard Model predicts their spins to be correlated. The degree of correlation depends on both the production mechanism and properties of the top quark. Any deviation from the Standard Model prediction can be an indicator for new physics phenomena. The thesis employs an advanced top quark reconstruction algorithm including dedicated identification of the up- and down-type quarks from the W boson decay.
Energy Research Abstracts
Author: Measurement of the Production Cross Sections for a Z Boson and One Or More B Jets in Pp Collisions at Sqrt(s)
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 39
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.