J/Psi and Psi' total cross sections and formation times from data for charmonium suppression in $pA$ collisions

Abstract

The recent data for E866 experiment on the x_F dependence for charmonium suppression in pA collisions at 800 GeV are analyzed using a time- and energy-dependent preformed charmonium absorption cross section σ_{abs}^ψ(τ,\sqrt{s}). For \sqrt{s}=10 GeV the initially (τ=0) produced premeson has an absorption cross section of σ_{pr}~3mb. At the same energy but for τ-> \infty one deduces for the total cross sections σ_{tot}^{J/Psi N}=(2.8\pm 0.3)mb, σ_{tot}^{J/Psi N}= (10.5\pm 3.6)mb. The date are compatible with a formation time τ_{1/2}=0.6 fm/c.