Double longitudinal-spin asymmetries in $J/\psi$ production at RHIC

TL;DR

This paper calculates the double longitudinal-spin asymmetry in $J/$ production at RHIC using NLO QCD, compares results with experimental data, and explores theoretical uncertainties with different LDMEs.

Contribution

It provides NLO QCD predictions for $A_{LL}$ in $J/$ production and assesses the impact of various LDMEs on theoretical uncertainties.

Findings

Predicted $A_{LL}$ values are consistent with PHENIX measurements.

For $p_t<5$ GeV, different LDMEs yield similar results.

Theoretical uncertainties are within experimental data tolerances.

Abstract

The double longitudinal-spin asymmetry, $A_{LL}$, of the $J/\psi$ production in polarized proton-proton collisions is presented in this paper at QCD next-to-leading order. It is found that the obtained values of $A_{LL}$ are in general consistent with the PHENIX measurements. Various sets of the long-distance matrix elements (LDMEs) are employed in our calculation to study the possible theoretical uncertainties. It is found that, for $p_t<5\gev$, all these LDMEs lead to almost the same results, which are within the tolerance of the experimental data uncertainties.