Antibaryons bound in nuclei
  We study the possibility of producing a new kind of nuclear systems which in addition to ordinary nucleons contain a few antibaryons (antiproton, antilambda, etc.). The properties of such systems are described within the relativistic mean-field model by employing G-parity transformed interactions for antibaryons. Calculations are first done for infinite systems and then for finite nuclei from He to Pb. It is demonstrated that the presence of a real antibaryon leads to a strong rearrangement of a target nucleus resulting in a significant increase of its binding energy and local compression. Noticeable effects remain even after the antibaryon coupling constants are reduced by factor 3-4 compared to G-parity motivated values. We have performed detailed calculations of the antibaryon annihilation rates in the nuclear environment by applying a kinetic approach. It is shown that due to significant reduction of the reaction Q-values, the in-medium annihilation rates should be strongly suppressed leading to relatively long-lived antibaryon-nucleus systems. Multi-nucleon annihilation channels are analyzed too. We have also estimated formation probabilities of bound antibaryon-nucleus systems in antiproton-nucleus reactions and have found that their observation will be feasible at the future GSI antiproton facility. Several observable signatures are proposed. The possibility of producing multi-quark-antiquark clusters is discussed. 
I.N. Mishustin, L.M. Satarov, T.J. Buervenich, H. Stoecker, W. Greiner