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.
http://hal.in2p3.fr/in2p3-00466986
Contributor : Swarna Bassava <>
Submitted on : Thursday, March 25, 2010 - 3:03:47 PM Last modification on : Tuesday, December 15, 2020 - 4:01:58 AM