Complete next-to-leading-order corrections to J/psi photoproduction in nonrelativistic quantum chromodynamics

TL;DR

This paper presents the first complete next-to-leading-order calculation of J/psi photoproduction in nonrelativistic QCD, including relativistic corrections for various color-octet states, and compares results with experimental data.

Contribution

It provides the first full NLO calculation with relativistic corrections for J/psi photoproduction within NRQCD, enhancing theoretical understanding.

Findings

Color octet mechanism is supported by data

Relativistic corrections significantly impact cross section predictions

Uncertainties in long-distance matrix elements remain a challenge

Abstract

We calculate the cross section of inclusive direct J/psi photoproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics, for the first time including the full relativistic corrections due to the intermediate ^1S_0^[8], ^3S_1^[8], and ^3P_J^[8] color-octet states. A comparison of our results to recent H1 data suggests that the color octet mechanism is indeed realized in J/psi photoproduction, although the predictivity of our results still suffers from uncertainties in the color-octet long-distance matrix elements.