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.
Cite
@article{arxiv.hep-ph/9802421,
title = {Inelastic Photoproduction at HERA: a Second Charmonium Crisis?},
author = {O. J. P. Eboli and E. M. Gregores and F. Halzen},
journal= {arXiv preprint arXiv:hep-ph/9802421},
year = {2009}
}
Comments
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