# Constraints for nuclear PDFs from the LHCb D-meson data

## TL;DR

This paper assesses how LHCb D-meson data at 5 TeV influences nuclear parton distribution functions, confirming compatibility with existing models and constraining gluon distributions without indicating non-linear QCD effects.

## Contribution

It introduces a detailed analysis of LHCb D-meson data impact on nuclear PDFs using the SACOT-mT formalism and reweighting methods, with careful treatment of theoretical uncertainties.

## Key findings

- LHCb D-meson data constrains gluon distributions in nuclear PDFs.
- No evidence of non-linear QCD effects beyond DGLAP evolution.
- Data compatible with EPPS16 and nCTEQ15 models.

## Abstract

We quantify the impact of LHCb D-meson measurements at $\sqrt{s}=5 \, {\rm TeV}$ on the EPPS16 and nCTEQ15 nuclear PDFs. In our study, the theoretical description of D-meson production is based on the recently developed SACOT-$m_{\rm T}$ variant of the general-mass variable-flavour-number formalism, and the impact on PDFs is estimated via reweighting methods. We pay special attention on the theoretical uncertainties known to us, and are led to exclude the $p_{\rm T}<3 \, {\rm GeV}$ region from our main analysis. The LHCb data can be accommodated well within EPPS16 and nCTEQ15, and the data provide stringent constraints on the gluons in the shadowing/antishadowing regions. No evidence of non-linear effects beyond standard DGLAP evolution is found even if the full kinematic region down to zero $p_{\rm T}$ is considered.