Probing transverse momentum dependent gluon distribution functions from hadronic quarkonium pair production

TL;DR

This paper proposes using hadronic quarkonium pair production to extract transverse momentum dependent gluon distributions, employing NRQCD and TMD factorization to analyze angular distributions for unpolarized hadrons.

Contribution

It introduces a novel method to probe TMD gluon distributions through quarkonium pair production using NRQCD and angular analysis.

Findings

Unpolarized and linearly polarized gluon distributions can be extracted.

TMD factorization is assumed at lowest order for this process.

Angular distributions provide key insights into gluon TMDs.

Abstract

The inclusive hadronic production of $\eta_Q$($\eta_c$ or $\eta_b$) pair is proposed to extract the transverse momentum dependent(TMD) gluon distribution functions. We use nonrelativistic QCD(NRQCD) for the production of $\eta_Q$. Under nonrelativistic limit TMD factorization for this process is assumed to make a lowest order calculation. For unpolarized initial hadrons, unpolarized and linearly polarized gluon distributions can be extracted by studying different angular distributions.