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

Values for the cross sections σΨNtot and σΨ′Ntot are of crucial importance, once one wants to understand nuclear suppression of J/Ψ(Ψ′) in a search for the quark gluon plasma. Quoted values are usually extracted from γN→J/Ψ(Ψ′)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 γN data lead to a value 2.8±0.12 mb<σtotΨN(s=10 GeV)<4.1±0.15 mb, which is a factor 3 larger than the VDM prediction. Errors are due to experimental input, and the corridor shows the theoretical uncertainty. We also derive from the data σtotΨ′N/σtotJ/ΨN≈4, where we could not estimate the theoretical uncertainty.