NLO QCD Corrections for $J/\psi+ c + \bar{c}$ Production in Photon-Photon Collision

TL;DR

This paper calculates the next-to-leading order QCD corrections for the process of J/psi production in photon-photon collisions, providing more accurate predictions and reducing discrepancies with experimental data.

Contribution

First NLO QCD correction calculation for two projectiles producing a three-body quarkonium state in photon-photon collisions within the NRQCD framework.

Findings

NLO corrections moderately increase the total cross section with a K factor of about 1.46 at LEP2 energy.

NLO corrections reduce the discrepancy between data and color-singlet calculations.

At future CEPC, NLO corrections are more significant with a K factor of about 1.76.

Abstract

The $\gamma+\gamma\rightarrow J/\psi+c+\bar{c}$ inclusive process is an extremely important subprocess in $J/\psi$ production via photon-photon scattering, like at LEP\uppercase\expandafter{\romannumeral2} or various types future electron-positron colliders. In this work we perform the next-to-leading(NLO) QCD corrections to this process in the framework of non-relativistic QCD(NRQCD) factorization formalism, the first NLO calculation for two projectiles to 3-body quarkonium inclusive production process. By setting the center-of-mass energy at LEP\uppercase\expandafter{\romannumeral2}, the $\sqrt{s}=197$ GeV, we conduct analyses of the $p_t^2$ distribution and total cross section of this process at the NLO accuracy. It turns out that the total cross section is moderately enhanced by the NLO correction with a $K$ factor of about 1.46, and hence the discrepancy between DELPHI data and color-singlet(CS) calculation is reduced while the color-octet(CO) contributions are still inevitable at this order. At the future Circular Electron-Positron Collider(CEPC), the NLO corrections are found to be more significant, with a $K$ factor of about 1.76.