# QCD Corrections to the Color-singlet $J/\psi$ Production in Deeply Inelastic Scattering at HERA

## TL;DR

This paper calculates QCD corrections to J/psi production in deep inelastic scattering at HERA, showing that corrections are significant but still insufficient to match experimental data, implying the need for color-octet contributions.

## Contribution

First calculation of QCD corrections to color-singlet J/psi production in DIS at HERA, highlighting the importance of color-octet mechanisms.

## Key findings

- QCD K-factors range from 0.85 to 2.38
- Perturbative expansion converges well at low transverse momentum
- Color-singlet cross section remains below experimental data

## Abstract

We present the first study of the QCD corrections to the color-singlet (CS) $J/\psi$ production in deeply inelastic $ep$ scattering at HERA. The $K$-factor ranges from $0.85$ to $2.38$ in the kinematic regions we study. In low transverse momentum regions, the $K$-factors is even smaller, and close to 1, which indicates good convergence of the perturbative expansion. With the QCD corrections, the CS cross section is still below the data. At least at QCD next-to-leading order, the color-octet mechanism is necessary to describe the data.