# The antinucleon-nucleon quasi-bound states: $J/\psi$ and atomic evidence

Abstract : The measurements of J/psi decays into photon, proton and antiproton show a strong enhancement at the proton-antiproton threshold not seen in the decays into neutral pion, proton and antiproton. What is the nature of this enhancement? A natural interpretation can be performed in terms of a classical model of nucleon-antinucleon interactions based on G-parity transformation. The observed proton-antiproton structure is the consequence of the strong attraction in the singlet S-wave state related predominantly to pion exchanges. Similar attractions generate near threshold: an isospin-zero virtual (or quasi-bound) state in singlet S-wave, an isospin-one quasi-bound state in triplet P-wave with total angular momentum one and an isospin-zero resonance in triplet P-wave with total angular momentum zero. These P-wave structures find support in the antiproton-atomic data.
Document type :
Conference papers

http://hal.in2p3.fr/in2p3-00149646
Contributor : Dominique Girod <>
Submitted on : Monday, May 28, 2007 - 10:11:07 AM
Last modification on : Friday, April 10, 2020 - 5:30:44 PM

### Citation

S. Wycech, B. Loiseau. The antinucleon-nucleon quasi-bound states: $J/\psi$ and atomic evidence. Eighth International Conference on Low Energy Antiproton Physics (LEAP '05), May 2005, Bonn-Juelich, Germany. pp.131-136, ⟨10.1063/1.2130149⟩. ⟨in2p3-00149646⟩

Record views