# Constraining gluon PDFs with quarkonium production

## TL;DR

This paper investigates how the positivity condition of eta_c-hadroproduction cross-section at NLO can provide constraints on the gluon parton distribution functions at low momentum fractions.

## Contribution

It introduces a novel method to constrain gluon PDFs using the positivity of quarkonium production cross-sections at NLO.

## Key findings

- Positivity of eta_c production cross-section constrains gluon PDFs.
- Provides a new approach for low-x gluon PDF determination.
- Enhances understanding of gluon behavior at low scales.

## Abstract

We explore how the positivity of the P_T-integrated eta_c-hadroproduction cross-section computed at NLO in alpha_s can set up constraints on the x-dependence of gluon PDFs at low scales.