A new state of baryonium

The recent discovery of a narrow resonance in the decay J/ψ→γpp̄ is described as a zero baryon number, deuteron-like singlet 1S0 state. The difference in binding energy of the deuteron (−2.225 MeV) and of the new state (−17.5 MeV) can be accounted for in a simple potential model with a λ·λ confining interaction.