Inelastic Photoproduction at HERA: a Second Charmonium Crisis?

Abstract

The measurement of the inelastic photoproduction of charmonium at HERA seems to have ignited a new charmonium crisis. The (already discredited) color singlet model fits the data for large charmonium energy fraction z, where the NRQCD model qualitatively fails. We here point out that by the straightforward inclusion of color singlet and octet processes in the soft color (color evaporation) scheme, the HERA data can be accommodated for all z. We anticipate that the color singlet model will fail at low z, as it does in hadroproduction.

10 pages, Revtex, uses epsfig.sty to include 4 postscript figures. Also available from the UW-Madison Phenomenology preprint archives at http://pheno.physics.wisc.edu/pub/preprints/1998/madph-98-1045.ps.Z or at ftp://pheno.physics.wisc.edu/pub/preprints/1998/madph-98-1045.ps.Z

References in corpus (1)

• Quarkonium Production at the Tevatron through Soft Colour Interactions

Cited by in corpus (11)

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• Color Evaporation Description of Inelastic Photo-Production of J/ψat HERA
• The Color Evaporation Model in Diffractive $J/\psi$ Photoproduction
• Diffractive quarkonium photoproduction in $pp$ and $pA$ collisions at the LHC: Predictions of the Resolved Pomeron model for the Run 2 energies
• Investigating the Transverse Single Spin Asymmetry in the Inelastic $J/\Psi$ photoproduction in $p^{\uparrow }p$ and $p^{\uparrow }A$ collisions
• Color Evaporation Induced Rapidity Gaps
• Testing Color Evaporation in Photon-Photon Production of J/Psi at CERN LEP II
• Soft Color Enhancement of the Production of J/psi's by Neutrinos