Measurement of the production and lepton charge asymmetry of $\textit{W}$ bosons in Pb+Pb collisions at $\sqrt{s_{\mathrm{\mathbf{NN}}}}=$ 2.76 TeV with the ATLAS detector

TL;DR

This paper reports on the measurement of W boson production and lepton charge asymmetry in Pb+Pb collisions at 2.76 TeV using the ATLAS detector, providing insights into nuclear effects on parton distributions.

Contribution

It presents the first detailed measurement of W boson yields and charge asymmetry in heavy-ion collisions at the LHC, comparing results with NLO QCD predictions.

Findings

W boson yields vary with the number of participating nucleons.

Lepton charge asymmetry shows consistency with theoretical models.

Results suggest potential nuclear modifications to parton distribution functions.

Abstract

A measurement of $\textit{W}$ boson production in lead-lead collisions at $\sqrt{s_{\mathrm{NN}}}=$2.76 TeV is presented. It is based on the analysis of data collected with the ATLAS detector at the LHC in 2011 corresponding to an integrated luminosity of 0.14 $\mathrm{nb}^{-1}$ and 0.15 $\mathrm{nb}^{-1}$ in the muon and electron decay channels, respectively. The differential production yields and lepton charge asymmetry are each measured as a function of the average number of participating nucleons $< N_{\mathrm{part}} >$ and absolute pseudorapidity of the charged lepton. The results are compared to predictions based on next-to-leading-order QCD calculations. These measurements are, in principle, sensitive to possible nuclear modifications to the parton distribution functions and also provide information on scaling of $\textit{W}$ boson production in multi-nucleon systems.