N ¯N exotics and antiprotonic atoms

S. Wycech (1) , B. Loiseau (1) , J.-P. Dedonder

1 LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies

The BES Collaboration measurements of J/ψ radiative decays into $ p{\bar p}$ indicate a strong enhancement at $ p {\bar p}$ threshold. In a related experiment a peak in the invariant π  +  π  − η′ mass is observed. It is shown that both structures may be related to a broad $ N{\bar N}$ quasi-bound state in the $^{11}S_{0} $ wave. The existence of this state finds additional support from the antiprotonic atom level widths. It is also explained by a traditional model of $ N \bar{N} $ interactions based on G-parity transformation. The level widths in H, D and He antiprotonic atoms and the radiochemical studies of $ {\bar p}$ capture in nuclei indicate the existence of another near-threshold quasi-bound state in a P wave.

Mots clés: $N\bar N$ exotics; Antiprotonic atoms

Domaines: Physique des Hautes Energies - Phénoménologie [hep-ph]

S. Wycech, B. Loiseau, J.-P. Dedonder. N ¯N exotics and antiprotonic atoms. Hyperfine Interactions, 2009, 194, pp.319-325. ⟨10.1007/s10751-009-0087-5⟩. ⟨in2p3-00466986⟩