Electroweak-boson production in p-Pb and Pb-Pb collisions at the LHC with ALICE

TL;DR

This paper reports measurements of electroweak boson production in proton-lead and lead-lead collisions at the LHC, providing insights into initial state effects and nuclear modifications of parton distribution functions using ALICE data.

Contribution

It presents new measurements of Z and W boson production in heavy-ion collisions at different energies, comparing results with theoretical models including nuclear modifications.

Findings

Electroweak boson yields are consistent with models including nuclear PDFs.

Data helps disentangle initial state effects from quark-gluon plasma phenomena.

Results provide constraints on nuclear parton distribution functions.

Abstract

Electroweak bosons are sensitive probes of the initial state of heavy-ion collisions, of which a precise knowledge is required in order to disentangle initial state effects from phenomena induced by the presence of the quark--gluon plasma (QGP). The production rate of the Z and W$^\pm$ bosons is especially sensitive to the nuclear modification of the Parton Distribution Functions (PDF), and the muonic decays (Z $\rightarrow \mu^+\mu^-$ and W$^\pm \rightarrow \mu^\pm \nu$) offer medium-blind processes carrying this information to the detector where it can be directly collected. In this contribution, new measurements of electroweak bosons in p--Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 8.16 TeV and Pb--Pb collisions at $\sqrt{s_{_{\rm NN}}}$ = 5.02 TeV measured by the ALICE Collaboration are reported. The data are collected at forward rapidity with the ALICE muon spectrometer and are compared to theoretical predictions with and without including nuclear modifications.