Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

J/psi production with NRQCD: HERA, Tevatron, RHIC and LHC

Mathias Butenschoen, Bernd A. Kniehl

TL;DR

The paper tests NRQCD factorization for J/psi production by performing a complete NLO calculation that includes both color-singlet and color-octet contributions. It conducts a multi-process fit of CO long-distance matrix elements to Tevatron and HERA data and then validates the fitted LDMEs against RHIC and LHC measurements, finding that CO channels are essential and the LDME values are broadly universal across processes. The results show that CO-based NRQCD accurately describes a wide range of data, while the conventional color-singlet model significantly underestimates the yields, thereby providing strong evidence for CO mechanisms and NRQCD factorization. The work also compares its fitting strategy to a parallel analysis and argues that a three-parameter, multi-process approach yields a more robust extraction of LDMEs.

Abstract

We report on our recent calculation of the inclusive direct photo- and hadroproduction of the J/psi meson at next-to-leading order within the factorization formalism of nonrelativistic QCD. We fit the color-octet (CO) long-distance matrix elements <O^(J/psi)(1S0[8])>, <O^(J/psi)(3S1[8])> and <O^(J/psi)(3P0[8])> to the transverse momentum (p_T) distributions measured by CDF at Fermilab Tevatron and by H1 at DESY HERA and show that they also successfully describe the p_T distributions from PHENIX at BNL RHIC and CMS at the CERN LHC as well as the photon-proton c.m. energy and (with worse agreement) the inelasticity distributions from H1. In all experiments, the CO processes are shown to be indispensable.

J/psi production with NRQCD: HERA, Tevatron, RHIC and LHC

TL;DR

The paper tests NRQCD factorization for J/psi production by performing a complete NLO calculation that includes both color-singlet and color-octet contributions. It conducts a multi-process fit of CO long-distance matrix elements to Tevatron and HERA data and then validates the fitted LDMEs against RHIC and LHC measurements, finding that CO channels are essential and the LDME values are broadly universal across processes. The results show that CO-based NRQCD accurately describes a wide range of data, while the conventional color-singlet model significantly underestimates the yields, thereby providing strong evidence for CO mechanisms and NRQCD factorization. The work also compares its fitting strategy to a parallel analysis and argues that a three-parameter, multi-process approach yields a more robust extraction of LDMEs.

Abstract

We report on our recent calculation of the inclusive direct photo- and hadroproduction of the J/psi meson at next-to-leading order within the factorization formalism of nonrelativistic QCD. We fit the color-octet (CO) long-distance matrix elements <O^(J/psi)(1S0[8])>, <O^(J/psi)(3S1[8])> and <O^(J/psi)(3P0[8])> to the transverse momentum (p_T) distributions measured by CDF at Fermilab Tevatron and by H1 at DESY HERA and show that they also successfully describe the p_T distributions from PHENIX at BNL RHIC and CMS at the CERN LHC as well as the photon-proton c.m. energy and (with worse agreement) the inelasticity distributions from H1. In all experiments, the CO processes are shown to be indispensable.

Paper Structure

This paper contains 5 sections, 2 figures, 1 table.

Table of Contents

  1. Introduction and Overview
  2. Fit to HERA and Tevatron data
  3. Predictions for further data
  4. Conclusions
  5. Comparison with Ref. Ma:2010yw

Figures (2)

  • Figure 1: NLO NRQCD predictions of $J/\psi$ hadro- and photoproduction resulting from the fit compared to the CDF Acosta:2004yw and H1 Adloff:2002exAaron:2010gz input data.
  • Figure 2: NLO NRQCD predictions of $J/\psi$ hadro- and photoproduction resulting from the fit compared to RHIC Adare:2009js, CMS CMSdata, and H1 Adloff:2002exAaron:2010gz data not included in the fit.