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

The recent data for E866 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. For charmonium-nucleon c.m. energy 10 GeV the initially produced premeson has an absorption cross sect ion of sigma(pr) similar or equal to 3 mb. At the same energy but for the d eveloped charmonium stares one deduces for me total cross sections sigma(to t)(J/psi N) = (2.8 +/- 0.3) mb, sigma(tot)(J/psi'N) = (10.5 +/- 3.6) mb. Th e date are compatible with a formation time tau(1/2) = 0.6 fm/c in the rest frame of the charmonium. (C) 2000 Published by Elsevier Science B.V. All r ights reserved.