Comprehensive evidence about a narrow $p \overline{p}$ state of mass 2.02 $GeV/c^2$

We report evidence for the existence of a narrow $p\overline{p}$ state with a mass of 2.02 GeV/c$^2$ and a width below 10 MeV/c$^2$ produced in $\pi^+p(\pi^-p)$ interactions at 20(12) GeV/c in six final states, proceeding via baryon exchange mechanism, that could be interpreted as a $baryonium$ candidate. The data come from a new analysis of WA56 experiment made with the CERN $\Omega$ spec trometer. Our results are based on the study of an unexplored kinematic region of baryon exchange processes, the central production of mesons. An agreement is found between our results and an ear lier observation of this state, and an explanation is given why it was not seen in several other experiments.