Neutron-skin effect and centrality dependence of high-$p_{\mathrm{T}}$ observables in nuclear collisions

TL;DR

This study investigates how the neutron-skin effect influences high-$p_{\mathrm{T}}$ observables in nuclear collisions at the LHC, highlighting its potential impact on peripheral collision measurements.

Contribution

It provides a quantitative analysis of the neutron-skin effect on various high-$p_{\mathrm{T}}$ observables and assesses the feasibility of detecting this effect experimentally.

Findings

Neutron-skin effect causes up to 20% changes in charged hadron and W boson production in peripheral collisions.

Direct photon observables are less sensitive to the neutron-skin effect due to uncertainties in nuclear PDFs.

The neutron-skin effect is significant for understanding electroweak phenomena in heavy-ion collisions.

Abstract

We report on our studies of the neutron-skin effects in high-$p_{\mathrm{T}}$ observables at the LHC. We study the impact of the neutron-skin effect on the centrality dependence of inclusive direct photon, high-$p_{\mathrm{T}}$ hadron and $W^{\pm}$ production in nuclear collisions at the LHC. The neutron-skin effect refers to the observation that in spherical heavy nuclei, the tail of the neutron distribution extends farther than the distribution of protons, which can affect observables sensitive to electroweak phenomena in very peripheral collisions. We quantify this effect for direct photons, charged hadrons and W bosons as a function of the collision centrality. In the case of direct photons we find that it will be difficult to resolve the neutron-skin effect, given the uncertainties in the nuclear PDFs and their spatial dependence. With charged hadrons and W's, however, up to 20~\% unambiguous effects are expected for most peripheral collisions.