Relativistic Correction to J/\psi Production at Hadron Colliders

TL;DR

This paper calculates relativistic corrections to J/ production at hadron colliders and finds these corrections are negligible, thus not resolving existing discrepancies between theory and experiment.

Contribution

It provides the first detailed calculation of relativistic corrections up to O(v^2) in J/ hadroproduction at Tevatron and LHC.

Findings

Relativistic corrections are about 1% of the cross section.

These corrections do not significantly improve agreement with experimental data.

Relativistic effects are too small to resolve the existing discrepancy.

Abstract

Relativistic corrections to the color-singlet J/\psi hadroproduction at the Tevatron and LHC are calculated up to O(v^2) in nonrelativistic QCD (NRQCD). The short distance coefficients are obtained by matching full QCD with NRQCD results for the subprocess g+g\to J/\psi+g. The long distance matrix elements are extracted from observed J/\psi hadronic and leptonic decay widths up to O}(v^2). Using the CTEQ6 parton distribution functions, we calculate the LO production cross sections and relativistic corrections for the process p+\bar{p}(p)\to J/\psi+X at the Tevatron and LHC. We find that the enhancement of O(v^2) relativistic corrections to the cross sections over a wide range of large transverse momentum p_t is negligible, only at a level of about 1 %. This tiny effect is due to the smallness of the correction to short distance coefficients and the suppression from long distance matrix elements. These results indicate that relativistic corrections can not help to resolve the large discrepancy between leading order prediction and experimental data for J/\psi production at the Tevatron.