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

Joerg Huefner; B. Z. Kopeliovich

doi:10.1016/S0370-2693(98)00257-3

paper

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

arXiv:hep-ph/9712297 · doi:10.1016/S0370-2693(98)00257-3

Abstract

Values for the cross sections $σ_{t o t}^{Ψ N}$ and $σ_{t o t}^{Ψ^{'} N}$ 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 $γ N \to J /Ψ (Ψ^{'}) N$ data via the 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 $γ N$ data lead to a value $2.8 \pm 0.12 mb < σ_{t o t}^{Ψ N} (s = 10 G e V) < 4.1 \pm 0.15 mb$ , 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 $σ_{t o t}^{Ψ^{'} N} / σ_{t o t}^{J /Ψ N} \approx 4$ , where we could not estimate the theoretical uncertainty.

13 pages, 2 Postscript figures

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

Abstract

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