# N ¯N exotics and antiprotonic atoms

Abstract : 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.
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Journal articles

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Submitted on : Thursday, March 25, 2010 - 3:03:47 PM
Last modification on : Tuesday, December 15, 2020 - 4:01:58 AM

### Citation

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

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