Constraints on the initial state of PbPb collisions via measurements of Z boson yields and azimuthal anisotropy at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV

Abstract

The CMS experiment at the LHC has measured the differential cross sections of Z bosons decaying to pairs of leptons, as functions of transverse momentum and rapidity, in lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The measured Z boson elliptic azimuthal anisotropy coefficient is compatible with zero, showing that Z bosons do not experience significant final-state interactions in the medium produced in the collision. Yields of Z bosons are compared to Glauber model predictions and are found to deviate from these expectations in peripheral collisions, indicating the presence of initial collision geometry and centrality selection effects. The precision of the measurement allows, for the first time, for a data-driven determination of the nucleon-nucleon integrated luminosity as a function of lead-lead centrality, thereby eliminating the need for its estimation based on a Glauber model.

Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/HIN-19-003 (CMS Public Pages)

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Cited by in corpus (10)

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• Centrality dependence of electroweak boson production in PbPb collisions at the LHC
• Correlations of event activity with hard and soft processes in $p$ + Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV at STAR
• Selection bias effects on high-$p_{\mathrm{T}}$ yield and correlation measurements in Oxygen+Oxygen collisions
• Performance of CMS muon reconstruction from proton-proton to heavy ion collisions
• Hard processes in multi-TeV ion collisions
• Measurement of the inclusive isolated-photon production cross section in pp and Pb$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV
• Geometric Bias and Centrality Dependence of Jet Quenching in High-Energy Nuclear Collisions