Abstract
Measurements of the Drell-Yan production of W and Z bosons at the LHC provide a benchmark of our understanding of perturbative QCD and probe the proton structure in a unique way. The ATLAS collaboration has performed new high precision measurements at a center-of-mass energy of 7 TeV. The measurements are performed for W+, W- and Z bosons integrated and as a function of the boson or lepton rapidity and the Z mass. Unprecedented precision is reached and strong constraints on Parton Distribution Functions, in particular the strange density are found. Z boson cross sections are also measured at center-of-mass energies of 8 TeV and 13 TeV, and cross-section ratios to the top-quark pair production have been derived. This ratio measurement leads to a cancellation of systematic effects and allows for a high precision comparison to the theory predictions. The production of jets in association with vector bosons is a further important process to study perturbative QCD in a multi-scale environment. The ATLAS collaboration has performed new measurements of Z boson plus jets cross sections, differential in several kinematic variables, in proton-proton collision data taken at a center-of-mass energy of 13 TeV. The measurements are compared to state-of-the art theory predictions. They are sensitive to higher-order pQCD effects, probe flavour and mass schemes and can be used to constrain the proton structure. In addition, a new measurement of the splitting scales of the kt jet-clustering algorithm for final states containing a Z boson candidate at a center-of-mass energy of 8 TeV is presented.
Highlights
The production of W and Z bosons via the Drell-Yan process is widely studied at the LHC experiments with proton-proton collision, including the ATLAS experiment [1]
A selection of seven of the most recent ATLAS results on vector boson physics will be presented: W and Z boson production cross section at 7 TeV [2] and 13 TeV [3]; ratio of ttover Z boson production cross section at 7, 8 and 13 TeV [4]; Z+jets production cross section at 13 TeV [5]; triple differential Z boson cross section at 8 TeV [6]; angular coefficients of Z boson leptons [7] and splitting scales of anti-kt algorithm clustered jets [8], both measured with 8 TeV data
The ATLAS result is compared with predictions obtained adopting different physics analyses.https://doi.org/10.1051/epjconf/201817203001Parton Distribution Functions (PDFs); in all cases, the predicted cross section ratio values are higher than those measured in data, clearly pointing out the need for improvements in the description of the proton structure
Summary
The production of W and Z bosons via the Drell-Yan process is widely studied at the LHC experiments with proton-proton collision, including the ATLAS experiment [1]. Those processes have a clear signature (especially in the lepton decay channels: Z → ll and W → lν) and are characterized by small background contamination. A selection of seven of the most recent ATLAS results on vector boson physics will be presented: W and Z boson production cross section at 7 TeV [2] and 13 TeV [3]; ratio of ttover Z boson production cross section at 7, 8 and 13 TeV [4]; Z+jets production cross section at 13 TeV [5]; triple differential Z boson cross section at 8 TeV [6]; angular coefficients of Z boson leptons [7] and splitting scales of anti-kt algorithm clustered jets [8], both measured with 8 TeV data
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