Prompt J/psi production in the Regge limit of QCD: From Tevatron to LHC

TL;DR

This paper investigates prompt J/psi-meson production at high energies using gluon Reggeization and nonrelativistic QCD, successfully predicting LHC measurements without free parameters.

Contribution

It introduces a novel approach combining gluon Reggeization with nonrelativistic QCD to predict J/psi production spectra at the LHC.

Findings

Good agreement with LHC data at 7 TeV without free parameters

Effective use of unintegrated gluon distributions derived from collinear PDFs

Validates gluon Reggeization hypothesis in high-energy QCD processes

Abstract

We study prompt J/psi-meson hadroproduction invoking the hypothesis of gluon Reggeization in t-channel exchanges at high energy and the factorization formalism of nonrelativistic quantum chromodynamics at the leading order in the strong-coupling constant alpha_s and the relative velocity of quarks v. The transverse-momentum distribution of direct and prompt J/psi-meson production measured at the Fermilab Tevatron fitted to obtain the nonperturbative long-distance matrix elements, which are used to predict prompt J/psi production spectra at the CERN LHC. At the numerical calculation, we adopt the Kimber-Martin-Ryskin and Blumlein prescriptions to derive unintegrated gluon distribution function of the proton from their collinear counterpart, for which we use the Martin-Roberts-Stirling-Thorne set. Without adjusting any free parameters, we find good agreement with measurements by the ATLAS, CMS and LHCb Collaborations at the LHC at the hadronic c.m. energy sqrt S=7 TeV.