Measurement of the angular coefficients in $Z$-boson events using electron and muon pairs from data taken at $\sqrt{s}=8$ TeV with the ATLAS detector

Abstract

The angular distributions of Drell-Yan charged lepton pairs around the $Z$-boson mass peak probe the underlying QCD dynamics of $Z$-boson production. This paper presents a measurement of the complete set of angular coefficients $A_{0-7}$ describing these distributions in the $Z$-boson Collins-Soper frame. The data analysed correspond to 20.3 fb${}^{-1}$ of $pp$ collisions at $\sqrt{s}=8$ TeV, collected by the ATLAS detector at the CERN LHC. The measurements are compared to the most precise fixed-order calculations currently available ($\mathcal{O}({\alpha }_s^2)$) and with theoretical predictions embedded in Monte Carlo generators. The measurements are precise enough to probe QCD corrections beyond the formal accuracy of these calculations and to provide discrimination between different parton-shower models. A significant deviation from the $\mathcal{O}({\alpha }_s^2)$ predictions is observed for $A_0-A_2$. Evidence is found for non-zero $A_{5,6,7}$, consistent with expectations.

84 pages plus author list + cover pages (101 pages total), 33 figures, 27 tables. Submitted to JHEP. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2014-10/

References in corpus (15)

• Parton distributions for the LHC
• Big-Bang Nucleosynthesis
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• New parton distributions for collider physics
• Event generation with SHERPA 1.1
• A parton shower algorithm based on Catani-Seymour dipole factorisation
• Vector boson production at hadron colliders: a fully exclusive QCD calculation at NNLO
• FEWZ 2.0: A code for hadronic Z production at next-to-next-to-leading order
• NLO vector-boson production matched with shower in POWHEG
• Measurement of the $Z/{\gamma }^{\ast }$ boson transverse momentum distribution in $pp$ collisions at $\sqrt{s}$ = 7 TeV with the ATLAS detector
• Electron and photon energy calibration with the ATLAS detector using LHC Run 1 data
• Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton-proton collision data
• Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton-proton collision data
• NNLOPS accurate Drell-Yan production
• First Measurement of the Angular Coefficients of Drell-Yan $e^{+}{e}^{-}$ pairs in the Z Mass Region from $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.96 TeV

Cited by in corpus (47)

• Measurement of the $W$-boson mass in pp collisions at $\sqrt{s}=7$ TeV with the ATLAS detector
• Electron efficiency measurements with the ATLAS detector using 2012 LHC proton-proton collision data
• Measurement of the W boson mass
• Measurement of $W^{\pm }Z$ production cross sections and gauge boson polarisation in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• The transverse momentum spectrum of weak gauge bosons at N${}^3$LL+NNLO
• Novel angular dependence in Drell-Yan lepton production via dimension-8 operators
• Forward Drell-Yan production at the LHC in the BFKL formalism with collinear corrections
• Electroweak Precision Tests of the Standard Model after the Discovery of the Higgs Boson
• Measurement of the Drell--Yan triple-differential cross section in $pp$ collisions at $\sqrt{s}=8$ TeV
• Search for new non-resonant phenomena in high-mass dilepton final states with the ATLAS detector
• Lam-Tung relation breaking in $Z^0$ hadroproduction as a probe of parton transverse momentum
• High-Energy Factorization for Drell-Yan process in $pp$ and $p\bar{p}$ collisions with new Unintegrated PDFs
• Compatibility and combination of world W-boson mass measurements
• Matching NNLO to parton shower using N${}^3$LL colour-singlet transverse momentum resummation in GENEVA
• Different polarization definitions in same-sign $WW$ scattering at the LHC
• Search for rare decays of Z and Higgs bosons to J$/\psi$ and a photon in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Azimuthal asymmetries in QCD hard scattering: infrared safe but divergent
• Vector Boson Scattering Processes: Status and Prospects
• Quantum tomography for collider physics: Illustrations with lepton pair production
• Measurement of the W-boson mass and width with the ATLAS detector using proton-proton collisions at $\sqrt{s}$ = 7 TeV
• Vector boson polarizations in the decay of the Standard Model Higgs
• NLO QCD corrections to polarised di-boson production in semi-leptonic final states
• Boosting the $H\to$ invisibles searches with $Z$ boson polarization
• Polarized Z bosons from the decay of a Higgs boson produced in association with two jets at the LHC
• Angular coefficients in W+j production at the LHC with high precision
• Precision QCD Physics at the LHC
• Opportunities and Challenges of Standard Model Production Cross Section Measurements at 8 TeV using CMS Open Data
• Rotation-invariant observables as Density Matrix invariants
• Boosting New Physics Searches in $t\bar{t}Z$ and $tZj$ Production with Angular Moments
• Lepton angular distributions of fixed-target Drell-Yan experiments in perturbative QCD and a geometric approach
• Dependencies of Lepton Angular Distribution Coefficients on the Transverse Momentum and Rapidity of$Z$ Bosons Produced in $pp$ Collisions at LHC
• A precise measurement of the Z-boson double-differential transverse momentum and rapidity distributions in the full phase space of the decay leptons with the ATLAS experiment at $\sqrt{s}$ = 8 TeV
• Vector Bosons and Jets in Proton Collisions
• Electroweak corrections to the angular coefficients in finite-$p_T$ $Z$-boson production and dilepton decay
• Role of the $Z$ polarization in the $H\to b\bar{b}$ measurement
• Amplitude-assisted tagging of longitudinally polarised bosons using wide neural networks
• Perturbative $T$-odd asymmetries in the Drell-Yan process revisited
• Defiducialization: Providing Experimental Measurements for Accurate Fixed-Order Predictions
• Astrophysical Constraints on Singlet Scalars at LHC
• Measurement of the polarizations of prompt and non-prompt J/$\psi$ and $\psi$(2S) mesons produced in pp collisions at $\sqrt{s}$ = 13 TeV
• $H\to Z\gamma$ decay and $CP$ violation
• A tale of $Z$+jet: SMEFT effects and the Lam-Tung relation
• Lepton angular distribution of $W$ boson productions
• $CP$ violation in the $HZZ$ vertex and left-right asymmetries
• The Forward Physics Facility at the High-Luminosity LHC
• The W and Z boson spin observables as messengers of new physics at LHC
• Use of $Z$ polarization in $e^{+}{e}^{-}\to ZH$ to measure the triple-Higgs coupling