Download or read book Measurement of the Cross section of High Transverse Momentum Vector Bosons Reconstructed as Single Jets and Studies of Jet Substructure in Pp Collisions at u221A s written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This article presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of $\sqrt{s}=7\;{\rm Te}{\rm V}$ and correspond to an integrated luminosity of $4.6\;{\rm f}{{{\rm b}}{̂-1}}$. The measurement is performed by reconstructing the boosted W or Z bosons in single jets. The reconstructed jet mass is used to identify the W and Z bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying W or Z boson, with transverse momentum ${{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}$ and pseudorapidity $
Download or read book Measurement of the Production Cross Sections for a Z Boson and One Or More B Jets in Pp Collisions at Sqrt s written by and published by . This book was released on 2014 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book A Measurement of the Ratio of the Production Cross Sections for W and Z Bosons in Association with Jets with the ATLAS Detector written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the ratio of the production cross sections for W and Z bosons in association with jets has been measured in proton-proton collisions at √s = 7 TeV with the ATLAS experiment at the Large Hadron Collider. The measurement is based on the entire 2011 dataset, corresponding to an integrated luminosity of 4.6 fb-1. Inclusive and differential cross-section ratios for massive vector bosons decaying to electrons and muons are measured in association with jets with transverse momentum pT > 30 GeV and jet rapidity.
Download or read book Measurements of the Associated Production of a Z Boson and B Jets in Pp Collisions at sqrt s written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of the associated production of a Z boson with at least one jet originating from a b quark in proton-proton collisions at $\sqrt{s}$ = 8 TeV are presented. Differential cross sections are measured with data collected by the CMS experiment corresponding to an integrated luminosity of 19.8 inverse femtobarns. Z bosons are reconstructed through their decays to electrons and muons. Cross sections are measured as a function of observables characterizing the kinematics of the b jet and the Z boson. Ratios of differential cross sections for the associated production with at least one b jet to the associated production with any jet are also presented. The production of a Z boson with two b jets is investigated, and differential cross sections are measured for the dijet system. Results are compared to theoretical predictions, testing two different flavour schemes for the choice of initial-state partons.
Download or read book Measurements of Jet Multiplicity and Differential Production Cross Sections of Z Jets Events in Proton proton Collisions at u221A s written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Measurements of the W Production Cross Sections in Association with Jets with the ATLAS Detector written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper presents cross sections for the production of a W boson in association with jets, measured in proton-proton collisions at \(\sqrt{s} = 7\) TeV with the ATLAS experiment at the large hadron collider. With an integrated luminosity of 4.6fb-1, this data set allows for an exploration of a large kinematic range, including jet production up to a transverse momentum of 1TeV and multiplicities up to seven associated jets. The production cross sections for W bosons are measured in both the electron and muon decay channels. Differential cross sections for many observables are also presented including measurements of the jet observables such as the rapidities and the transverse momenta as well as measurements of event observables such as the scalar sums of the transverse momenta of the jets. As a result, the measurements are compared to numerous QCD predictions including next-to-leading-order perturbative calculations, resummation calculations and Monte Carlo generators.
Download or read book Measurement of Inclusive Jet Cross sections in Pp and PbPb Collisions at sqrt s NN written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Inclusive jet spectra from pp and PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV, collected with the CMS detector at the LHC, are presented. Jets are reconstructed with three different distance parameters for transverse momentum ($p_{\mathrm{T}}$) greater than 70 GeV/$c$ and pseudorapidity $
Download or read book Measurement of the Cross Section for W boson Production in Association with Jets in Ppbar Collisions at S written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the cross section for W-boson production in association with jets in p{bar p} collisions at √s = 1.96 TeV. The analysis uses a data sample corresponding to an integrated luminosity of 320 pb−1 collected with the CDF II detector. W bosons are identified in their electron decay channel and jets are reconstructed using a cone algorithm. For each W + ≥ n-jet sample (n = 1-4) we measure?(p{bar p} → W + ≥ n-jet) x?(W → e?) with respect to the transverse energy E{sub T} of the nth-highest E{sub T} jet above 20 GeV, for a restricted W → e? decay phase space. The cross sections, corrected for all detector effects, can be directly compared to particle level W + jet(s) predictions. We present here comparisons to leading order and next-to-leading order predictions.
Download or read book Measurement of the Jet Mass in Highly Boosted T tbar Events from Pp Collisions at sqrt s written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The first measurement of the jet mass m[jet] of top quark jets produced in t t-bar events from pp collisions at sqrt(s) = 8 TeV is reported for the jet with the largest transverse momentum pt in highly boosted hadronic top quark decays. The data sample, collected with the CMS detector, corresponds to an integrated luminosity of 19.7 inverse femtobarns. The measurement is performed in the lepton+jets channel in which the products of the semileptonic decay t to bW with W to l nu where l is an electron or muon, are used to select t t-bar events with large Lorentz boosts. The products of the fully hadronic decay t to bW with W to q q'-bar are reconstructed using a single Cambridge-Aachen jet with distance parameter R=1.2, and pt>400 GeV. The t t-bar cross section as a function of m[jet] is unfolded at the particle level and is used to test the modelling of highly boosted top quark production. The peak position of the m[jet] distribution is sensitive to the top quark mass m[t], and the data are used to extract a value of m[t] to assess this sensitivity.
Download or read book Physics with Jets in Association with a Z Boson in Pp collisions with the ATLAS Detector at the Large Hadron Collider written by and published by . This book was released on 2013 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the measurements of the production cross section of jets in association with a Z boson in pp-collisions at √s = 7 TeV with an integrated luminosity of ∫Ldt = 36-1 and ∫Ldt = 4.6 fb-1 recorded by the ATLAS experiment at the Large Hadron Collider in Geneva. Inclusive and differential Z(→e+e-) + jets cross sections are measured for jets with a transverse momentum pT(jet) > 30 GeV and rapidity |y(jet)|
Download or read book Measurement of Differential Production Cross sections for a Z Boson in Association with B jets in 7 TeV Proton proton Collisions with the ATLAS Detector written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report measurements of differential production cross-sections of a Z boson in association with b-jets in pp collisions at √ s = 7 TeV. The data analysed correspond to an integrated luminosity of 4.6 fb-1 recorded with the ATLAS detector at the Large Hadron Collider. Particle-level cross-sections are determined for events with a Z boson decaying into an electron or muon pair, and containing b-jets. For events with at least one b-jet, the cross-section is presented as a function of the Z boson transverse momentum and rapidity, together with the inclusive b-jet cross-section as a function of b-jet transverse momentum, rapidity and angular separations between the b-jet and the Z boson. For events with at least two b-jets, the cross-section is determined as a function of the invariant mass and angular separation of the two highest transverse momentum b-jets, and as a function of the Z boson transverse momentum and rapidity. Lastly, results are compared to leading-order and next-to-leading-order perturbative QCD calculations.
Download or read book Transverse Momentum Spectra of B Jets in PPb Collisions at u221A sNN written by and published by . This book was released on 2016 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of b jet transverse momentum (pT) spectra in protonlead (pPb) collisions using a dataset corresponding to about 35 nb-1 collected with the CMS detector at the LHC. Jets from b quark fragmentation are found by exploiting the long lifetime of hadrons containing a b quark through tagging methods using distributions of the secondary vertex mass and displacement. Extracted cross sections for b jets are scaled by the effective number of nucleon-nucleon collisions and are compared to a reference obtained from PYTHIA simulations of pp collisions. Furthermore, the PYTHIA-based estimate of the nuclear modification factor is found to be 1.22±0.15 (stat+syst pPb)_0.27 (syst PYTHIA) averaged over all jets with pT between 55 and 400 GeV/c and with.
Download or read book Measurement of the Cross Section for W boson Production in Association with Jets in Ppbar Collisions at S 1 2 written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the cross section for W-boson production in association with jets in p{bar p} collisions at √s = 1.96 TeV. The analysis uses a data sample corresponding to an integrated luminosity of 320 pb−1 collected with the CDF II detector. W bosons are identified in their electron decay channel and jets are reconstructed using a cone algorithm. For each W + ≥ n-jet sample (n = 1-4) we measure [sigma](p{bar p} → W + ≥ n-jet) x [Beta](W → e[nu]) with respect to the transverse energy E{sub T} of the nth-highest E{sub T} jet above 20 GeV, for a restricted W → e[nu] decay phase space. The cross sections, corrected for all detector effects, can be directly compared to particle level W + jet(s) predictions. We present here comparisons to leading order and next-to-leading order predictions.
Download or read book Measurement of the Production Cross Section of Jets in Association with a Z Boson in 8 TeV Proton proton Collisions with the ATLAS Detector written by Rodger Mantifel and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "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." --
Download or read book Differential Cross Section Measurements for the Production of a W Boson in Association with Jets in Proton u2013 proton Collisions at u221A s written by and published by . This book was released on 2014 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Measurement of the Production and Differential Cross Sections of W W Bosons in Association with Jets in p bar p Collisions at sqrt s written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, we present a measurement of the W-boson-pair production cross section in pp¯ collisions at 1.96 TeV center-of-mass energy and the first measurement of the differential cross section as a function of jet multiplicity and leading-jet energy. The W+W– cross section is measured in the final state comprising two charged leptons and neutrinos, where either charged lepton can be an electron or a muon. Using data collected by the CDF experiment corresponding to 9.7 fb–1 of integrated luminosity, a total of 3027 collision events consistent with W+W– production are observed with an estimated background contribution of 1790±190 events. The measured total cross section is ?(pp¯→W+W–) = 14.0 ± 0.6(stat)+1.2–1.0 (syst)±0.8 (lumi) pb, consistent with the standard model prediction.
Download or read book Measurement of Charged Jet Production Cross Sections and Nuclear Modification in P Pb Collisions at mml written by and published by . This book was released on 2015 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Charged jet production cross sections in p-Pb collisions at √s(NN) = 5.02 TeV measured with the ALICE detector at the LHC are presented. Using the anti-kT algorithm, jets have been reconstructed in the central rapidity region from charged particles with resolution parameters R = 0.2 and R = 0.4. The reconstructed jets have been corrected for detector effects and the underlying event background. To calculate the nuclear modification factor, R-pPb, of charged jets in p-Pb collisions, a pp reference was constructed by scaling previously measured charged jet spectra at √s = 7 TeV. In the transverse momentum range 20 ≤ pT, ch jet ≤ 120 GeV/c, R-pPb is found to be consistent with unity, indicating the absence of strong nuclear matter effects on jet production. Major modifications to the radial jet structure are probed via the ratio of jet production cross sections reconstructed with the two different resolution parameters. In conclusion, this ratio is found to be similar to the measurement in pp collisions at √s = 7 TeV and to the expectations from PYTHIA pp simulations and NLO pQCD calculations at √s(NN) = 5.02 TeV.
