ParisNN¯potential constrained by recent antiprotonic-atom data andn¯ptotal cross sections

Abstract

We report on an updated optical Paris nucleon-antinucleon potential. The long- and intermediate-range parts are obtained by G-parity transformation of the Paris nucleon-nucleon potential based on a theoretical dispersion-relation treatment of the correlated and uncorrelated two-pion exchange. The parametrized real and imaginary short range parts are determined by fitting not only the existing experimental data included in the 1999 version of the Paris nucleon-antinucleon potential, but also the recent antiprotonic-hydrogen data and antineutron-proton total cross sections. The description of the experimental observables is improved. Only this readjusted potential generates an isospin zero 1S0, 52 MeV broad quasi-bound state at 4.8 MeV below the threshold. Recent BES data on J/psi decays could support the existence of such a state.