J/ψN and ψ′N total cross sections from photoproduction data:: failure of vector dominance

Values for the cross sections sigma(tot)(Psi N) and sigma(tot)(Psi'N) are of crucial importance, once one wants to understand nuclear suppression of J/Psi(Psi') in a search for the quark gluon plasma. Quoted values an usually extracted from gamma N --> J/Psi(Psi')N data via the single channel vector dominance model (VDM) and are very small compared with expectations from QCD. The validity of QCD is questioned. When the VDM is extended to a multi-channel case, the gamma N data lead to a value 2.8+/-0.12 mb < sigma(tot)(Psi N)(root s = 10 GeV) < 4.1 +/- 0.15 mb, which is a factor 3 larger than the VBM prediction. Errors are due to experimental input, and the corridor shows the theoretical uncertainty. We also derive from the data sigma(tot)(Psi'N)/sigma(tot)(J/Psi N)approximate to 4, where we could not estimate the theoretical uncertainty. (C) 1998 Elsevier Science B.V, All rights reserved.