Probing the valence quark region of nucleons with Z bosons at LHCb

TL;DR

This paper discusses LHCb measurements of Z boson production and charm jets at high momentum fractions, providing new insights into the valence quark structure and intrinsic charm component of nucleons, and constraining nuclear parton distributions.

Contribution

It presents new LHCb measurements that probe the valence quark region and intrinsic charm in nucleons, comparing them with advanced parton distribution function models.

Findings

Evidence for a valence-like intrinsic-charm component in the proton

New constraints on partonic structure of nucleons in nuclei

Comparison with state-of-the-art PDF calculations

Abstract

In this high-$x$ region, both the flavour content and structure of the nucleon parton distribution functions remains relatively poorly known. New LHCb measurements of Z and charm jet associated production could indicate a valence-like intrinsic-charm component in the proton wave function, and measurements of Z production in pPb collisions provide new constraints on the partonic structure of nucleons bound inside nuclei. Here we will discuss these new LHCb measurements and comparisons with state-of-the-art parton distribution function calculations.