J/psi plus jet associated production in two-photon collisions at next-to-leading order

TL;DR

This work computes the next-to-leading-order cross section for inclusive $J/\psi$ plus jet production in $\gamma\gamma$ collisions within the NRQCD framework, including feed-down from heavier charmonia. The authors develop a full analytic treatment of virtual and real QCD corrections, renormalization of QCD parameters and NRQCD operators, and a phase-space slicing method to isolate IR singularities, assembling a finite NLO prediction for direct photoproduction. The study demonstrates large fragmentation-like contributions at NLO and a substantial reduction in renormalization-scale uncertainty, while highlighting the need to incorporate resolved-photoproduction at NLO for complete, collider-ready predictions (e.g., TESLA). Overall, the results provide a crucial step toward robust tests of NRQCD factorization in two-photon processes and guide future refinements with full resolved-channel corrections.

Abstract

We calculate the cross section of J/psi plus jet inclusive production in gamma gamma collisions at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics (NRQCD) focusing on direct photoproduction. Apart from direct J/psi production, we also include the feed-down from directly-produced chi_{cJ} and psi' mesons. We discuss the analytical calculation, in particular the treatment of the various types of singularities and the NRQCD operator renormalization, in some detail. We present theoretical predictions for the future e^+e^- linear collider TESLA, taking into account both brems- and beamstrahlung.

Figures (3)

• Figure 1: Tree-level Feynman diagrams pertinent to the partonic subprocess (\ref{['eq:ccg']}).
• Figure 2: One-loop Feynman diagrams pertinent to the partonic subprocess (\ref{['eq:ccg']}).
• Figure :