W and Z boson production in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV

TL;DR

This paper reports measurements of W and Z boson production in proton-lead collisions at 5.02 TeV, providing insights into nuclear effects on parton distributions and collision dynamics at the LHC.

Contribution

First measurement of W and Z boson production in p-Pb collisions at 5.02 TeV, including cross sections, charge asymmetry, and centrality dependence, with comparisons to theoretical models.

Findings

Z-boson production cross section measured in specified rapidity range.

W-boson decay muon charge asymmetry determined.

W-boson production scales with the number of binary collisions.

Abstract

The W and Z boson production was measured via the muonic decay channel in proton-lead collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV at the Large Hadron Collider with the ALICE detector. The measurement covers backward ($-4.46 < y_{\rm cms} < -2.96$) and forward ($2.03 < y_{\rm cms} < 3.53$) rapidity regions, corresponding to Pb-going and p-going directions, respectively. The Z-boson production cross section, with dimuon invariant mass of $60<m_{\mu\mu}<120$ GeV/$c^2$ and muon transverse momentum ($p_{\rm T}^\mu$) larger than 20 GeV/$c$, is measured. The production cross section and charge asymmetry of muons from W-boson decays with $p_{\rm T}^\mu>10$ GeV/$c$ are determined. The results are compared to theoretical calculations both with and without including the nuclear modification of the parton distribution functions. The W-boson production is also studied as a function of the collision centrality: the cross section of muons from W-boson decays is found to scale with the average number of binary nucleon-nucleon collisions within uncertainties.