Production and polarization of $S$-wave quarkonia in potential nonrelativistic QCD

TL;DR

This paper uses potential nonrelativistic QCD to compute long-distance matrix elements for S-wave quarkonia, improving predictions of production rates and polarization, and aligning well with LHC data.

Contribution

It introduces a method to reduce unknowns in LDME calculations, enhancing the predictive power of nonrelativistic QCD for quarkonium production.

Findings

Enhanced agreement with LHC data on cross sections.

Improved determinations of LDMEs for quarkonia.

Predictions of polarization states consistent with experiments.

Abstract

Based on the potential nonrelativistic QCD formalism, we compute the nonrelativistic QCD long-distance matrix elements (LDMEs) for inclusive production of $S$-wave heavy quarkonia. This greatly reduces the number of nonperturbative unknowns and brings in a substantial enhancement in the predictive power of the nonrelativistic QCD factorization formalism. We obtain improved determinations of the LDMEs and find cross sections and polarizations of $J/\psi$, $\psi(2S)$, and excited $\Upsilon$ states that agree well with LHC data. Our results may have important implications in pinning down the heavy quarkonium production mechanism.