Charmonium production in antiproton-nucleus reactions at low energies

TL;DR

This paper models charmonium production in low-energy antiproton-nucleus reactions using the Glauber model, highlighting the potential to measure charmonium-nucleon dissociation cross sections and the importance of nuclear density profiles.

Contribution

It provides a detailed theoretical analysis of charmonium production near threshold, incorporating formation length and nuclear density effects, relevant for the PANDA experiment at FAIR.

Findings

Charmonium production at 3-10 GeV/c is unaffected by formation length effects.

Production cross sections can help determine charmonium-nucleon dissociation cross sections.

Nuclear density profiles significantly influence the interpretation of transparency ratios.

Abstract

The J/\Psi(1S) and \Psi'(2S) production near threshold in antiproton-nucleus reactions is calculated on the basis of the Glauber model. The model takes into account the antiproton (pre)absorption, proton Fermi motion, and charmonium formation length. We confirm earlier prediction that the charmonium production in $\bar pA$ collisions at $p_{lab}=3-10$ GeV/c is not influenced by formation length effects and is very well suited to determine the genuine charmonium-nucleon dissociation cross sections. The comparison is performed with the J/\Psi photoproduction at high energies, where formation length effects play a very important role. However, we demonstrate that the detailed structure of the proton and neutron density profiles has to be taken into account, if one wants to extract information on the J/\Psi N dissociation cross section from J/\Psi transparency ratios. These studies are relevant for the upcoming PANDA experiment at FAIR.