Heavy quarkonium production and polarization

TL;DR

This paper develops a QCD factorization approach for heavy quarkonium production at high transverse momentum, incorporating both leading and next-to-leading power contributions, and analyzes polarization effects.

Contribution

It introduces a formalism that includes NLP contributions in heavy quarkonium production, improving theoretical predictions at collider energies.

Findings

NLP channels favor longitudinal polarization.

Reproduces large enhancements seen in NLO calculations.

Estimates fragmentation functions within non-relativistic QCD.

Abstract

We present a perturbative QCD factorization formalism for the production of heavy quarkonia of large transverse momentum $p_T$ at collider energies, which includes both the leading power (LP) and next-to-leading power (NLP) contributions to the cross section in the $m_Q^2/p_T^2$ expansion for heavy quark mass $m_Q$. We estimate fragmentation functions in the non-relativistic QCD formalism, and reproduce the bulk of the large enhancement found in explicit NLO calculations in the color singlet model. Heavy quarkonia produced from NLP channels prefer longitudinal polarization.