Last year the E866-group of the Fermilab measured the cursive Greek chiF dependence of J/Ψ and Ψ′ suppression in pA collisions. We discuss two of the effects found in that experiment with regard to color coherence effects: the different suppression of the J/Ψ and the Ψ′ at cursive Greek chiF < 0 and the significant suppression of both at large cursive Greek chiF. The small cursive Greek chiF regions is dominated by fully formed charmonium states and thus enables us to discuss the formation time and the cross section of the different charmonium states. In the large cursive Greek chiF region the interaction of the charmonium states with nuclear matter has to be described by partonic degrees of freedom, because in that kinematic domain the formation time is much larger than the nuclear radii. The understanding of this region will be crucial for the interpretation of the data of the future heavy ion colliders RHIC and LHC.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics