Download or read book Measurements of Vector Bosons Produced in Association with Jets written by and published by . This book was released on 2008 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The latest D0 and CDF measurements of the W + jets and Z/[gamma]* + jets processes are described, along with a discussion of the comparisons that have been made to LO and NLO perturbative QCD predictions. The direct production of W{sup {+-}}/Z bosons in association with jets is a process of crucial importance at hadron collider experiments. The presence of a vector boson in the hard scatter means that these interactions occur at a scale that should make perturbative QCD applicable, and thus it is an excellent channel to test such predictions. Furthermore, many of the potential discovery channels for the Higgs boson and beyond standard model processes share a final state signature with the W{sup {+-}}/Z + jets process. It is thus vital for the success of existing and future hadron collider experiments that this process is understood, and recently there has been a huge amount of work put into the modeling of this process, with the appearance of many new Monte Carlo generators that are already widely used at both the Tevatron and LHC. In Sections 2 and 3 the latest W + jets and Z/[gamma]* + jets measurements from the Tevatron are presented, and in Section 4 we discuss the results and implications of some of the theory comparisons that have thus far been made.
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 Z Boson Transverse Momentum Distribution and ZZ and WZ Production written by Mika Vesterinen and published by Springer Science & Business Media. This book was released on 2012-06-30 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work develops novel data analysis techniques enabling aspects of the Standard Model of particle physics to be tested with unprecedented precision using data from the DZero experiment at the high energy “Tevatron” proton-antiproton collider at Fermilab, Chicago. Vesterinen's measurements of the transverse momentum of Z bosons using the novel variable φ* have exposed deficiencies in the current state-of-the-art theoretical predictions for vector boson production at hadron colliders. These techniques are now being used in the experiments at CERN’s Large Hadron Collider (LHC) and have stimulated considerable interest in the theoretical particle physics community. Furthermore, Vesterinen's measurements of the cross sections for the production of pairs of vector bosons (WZ and ZZ) are to date the most precise ever made.
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 sqrt 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 study 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 Associated Production of Z Bosons and Jets in P pbar Collisions at the Tevatron written by and published by . This book was released on 2009 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: Higher order QCD corrections to W and Z boson production do not only manifest themselves in the generation of high transverse momenta of the weak bosons, but these QCD effects become directly visible in the production of jets in association with the weak bosons. Studying these processes is not only interesting from the perspective of testing perturbative QCD, but also to constrain a major background to many Standard Model (SM) of non-SM physics signals, e.g. top pair and single top production, searchers for the Higgs boson, leptoquarks and supersymmetric particles. This thesis describes a measurement of Z/[gamma]* + jets production in p$\bar{p}$ collisions at √s = 1.96 TeV in the decay channel Z/[gamma]* → [mu]+[mu]-. An integrated luminosity of L≈ 1fb-1 collected by the D0 detector at the Tevatron between August 2002 and February 2006 has been used. Differential production cross sections as function of the transverse energy of the first, second and third leading jet are measured. The distributions are corrected for acceptance and migration effects back to hadron level using an iterative unfolding method. Comparison of the measured cross sections to event generators, which include part of the higher order corrections are presented.
Download or read book Measurement of Z gamma B jet Production Cross Section in p bar p Collisions at sqrt s written by and published by . This book was released on 2012 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book A Beauty ful Boson written by Giulia Di Gregorio and published by Springer Nature. This book was released on 2023-01-01 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: The analysis described in this thesis is the search for the Higgs boson, decaying into bb pair, in the associated production with a vector boson, in the extreme Higgs boson transverse momentum region where the Higgs boson is reconstructed using the large-R jet technique. The use of the large-R jets allows to add a part of the phase space unexplored so far, which is particularly sensitive to possible new physics. The analysed data have been collected at LHC by the ATLAS detector between 2015 and 2018 at a centre-of-mass energy of √s = 13 TeV. The same dataset has been used to perform the differential pp → ZH and pp → WH cross-section measurements used to extract the information on the Higgs couplings and to put limits on Beyond the Standard Model effects. Furthermore the analysis has been re-used to perform a cross-section measurement of the diboson ZZ and WZ processes because the diboson and the Higgs processes have a similar topology. For the first time the ZZ(bb) and WZ(bb) cross-sections are measured at √s = 13 TeV and the observed cross-section measurements are consistent with the Standard Model predictions.
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 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 Jet Production Rates in Association with W and Z Bosons in Pp Collisions at sqrt s written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of jet production rates in association with W and Z bosons for jet transverse momenta above 30 GeV are reported, using a sample of proton-proton collision events recorded by CMS at sqrt(s) = 7 TeV, corresponding to an integrated luminosity of 36 inverse picobarns. The study includes the measurement of the normalized inclusive rates of jets sigma(V +>= n jets)/sigma(V), where V represents either a W or a Z. In addition, the ratio of W to Z cross sections and the W charge asymmetry as a function of the number of associated jets are measured. A test of Berends--Giele scaling at sqrt(s) = 7 TeV is also presented. The measurements provide a stringent test of perturbative-QCD calculations and are sensitive to the possible presence of new physics. The results are in agreement with the predictions of a simulation that uses explicit matrix element calculations for final states with jets.
Download or read book The Beauty and the Boost A Higgs Boson Tale written by Brian Moser and published by Springer Nature. This book was released on 2023-09-19 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Precision measurements of the Higgs boson’s properties are a powerful tool to look for deviations from the predictions of the Standard Model (SM) of particle physics. The 139/fb of proton-proton collision data which have been collected by the ATLAS experiment during Run 2 of the LHC, offer an opportunity to investigate rare Higgs-boson topologies, which are particularly sensitive to new physics scenarios but experimentally difficult to access. Several such measurements, which target Higgs-boson decays to heavy-flavour quarks, as well as their combinations are presented in this thesis. A novel analysis that measures Higgs-boson production in association with a heavy vector boson V (VH, with V=W,Z) at high energies is presented. Dedicated Higgs-boson reconstruction techniques are applied to reconstruct the highly Lorentz-boosted Higgs-boson decays into pairs of bottom quarks. The measurement is subsequently combined with a VH cross-section measurement at low and intermediate pT(V) to provide a differential cross-section measurement in kinematic fiducial volumes over the largest possible pT(V) range. All cross-section measurements agree with the SM predictions within relative uncertainties that range from 30% to 300%. The results are furthermore interpreted as limits on the parameters of a SM effective field theory. Finally, a combination of measurements of Higgs decays to heavy-flavour quarks is used to experimentally determine that the Higgs-boson coupling to charm quarks is weaker than to bottom quarks, as predicted by the SM. The target audience for the thesis are physicists and physics students, in particular those with a background in high energy physics.
Download or read book Measurement of the Transverse Momentum Spectra of Weak Vector Bosons Produced in Proton proton 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: The transverse momentum spectra of weak vector bosons are measured in the CMS experiment at the LHC. The measurement uses a sample of proton-proton collisions at sqrt(s) = 8 TeV, collected during a special low-luminosity running that corresponds to an integrated luminosity of 18.4 inverse-picobarns. The production of W bosons is studied in both electron and muon decay modes, while the production of Z bosons is studied using only the dimuon decay channel. The ratios of W- to W+ and Z to W differential cross sections are also measured. The measured differential cross sections and ratios are compared with theoretical predictions up to next-to-next leading order in QCD.
Download or read book Measurement of VH H Bb Production as a Function of the Vector boson Transverse Momentum in 13 TeV Pp Collisions with the ATLAS Detector written by Anne Kathrin Becker and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Cross-sections of associated production of a Higgs boson decaying into bottomquark pairs and an electroweak gauge boson, W or Z, decaying into leptons are measured as a function of the gauge boson transverse momentum. The measurements are performed in kinematic fiducial volumes defined in the 'simplified template cross-section' framework. The results are obtained using 79.8 fb−1 of proton-proton collisions recorded by the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. All measurements are found to be in agreement with the Standard Model predictions, and limits are set on the parameters of an effective Lagrangian sensitive to modifications of the Higgs boson couplings to the electroweak gauge bosons
Download or read book Measurement of the Associated Production of Z Bosons and Jets in Pp Collisions at the Tevatron written by Britta Tiller and published by . This book was released on 2009 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book V jets Background and Systematic Uncertainties in Top Quark Analyses written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Vector boson production in association with jets is an important process to test perturbative quantum chromodynamics and also a background process in top quark analyses. Measurements on vector boson production in association with light and heavy flavour jets are presented, performed by the D0 and CDF collaborations at the Tevatron as well as the ATLAS and CMS experiments at LHC. Techniques applied in top quark analyses to estimate the vector boson+jets background are also discussed.
Download or read book Measurement of Jet Production in Association with a W Boson at Atlas written by Imai Jen-La Plante and published by . This book was released on 2011 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study examines the associated production of jets with a W boson, identified by the decay W & rarr; enu. The measurement uses the full data sample collected by the ATLAS experiment during the inaugural year of proton-proton collisions with center-of-mass energy s = 7 TeV at the Large Hadron Collider. Cross sections are presented for W & rarr; enu events with each jet multiplicity from zero through four or more jets and as a function of jet transverse momenta, the scalar sum of jet and lepton transverse momenta, the invariant mass of jets, and angular distributions. The results represent the first experimental test of perturbative QCD predictions with next-to-leading order precision for W + 4 jets.
