English

How well does NRQCD describe quarkonium production?

High Energy Physics - Phenomenology 2026-01-28 v1

Abstract

The question how well nonrelativistic QCD (NRQCD) factorization can describe quarkonium production has been subject to debate since its invention. We review our recent reanalysis of a classic next-to-leading order color octet (CO) long distance matrix element (LDME) fit to large transverse momentum pTp_T J/ψJ/\psi and ηc\eta_c LHC production data. Our analysis differs from previous analyses of this kind not only by implementing for the first time a systematic treatment of scale uncertainties, but also by scrutinizing a much broader range of observables. Surprisingly, J/ψJ/\psi hadroproduction is well described up to the highest measured values of pTp_T. Potential NRQCD based relations nontrivially lead to a perfect description of Υ(nS)\Upsilon(nS) production data. Furthermore, J/ψJ/\psi production in γp\gamma p and γγ\gamma \gamma collisions is, contrary to prevailing conceptions, reproduced down to pT=1p_T=1 GeV, as long as the region of large inelasticity zz is excluded. The overall picture is much rosier than usually perceived, the more so as the remaining discrepancies appear in phase space regions where solutions via varying kinds of resummations have been proposed.

Keywords

Cite

@article{arxiv.2601.19619,
  title  = {How well does NRQCD describe quarkonium production?},
  author = {Mathias Butenschoen},
  journal= {arXiv preprint arXiv:2601.19619},
  year   = {2026}
}

Comments

7 pages, 16 figures, contribution to "QCD at the Extremes (QCDEX2025)"

R2 v1 2026-07-01T09:22:18.739Z