A search for long-lived low mass states coupling to e+e-

Since the observation by the EPOS group at GS in 1985 of correlated electron-positron pair emission in superheavy ion-atom collision systems there have been many attempts to explain the phenomenon. The EPOS coincidence data show a series of narrow sum-energy lines in the laboratory kinetic energy range 610--820 keV. Recently, similar observations were reported by another group. For lack of conventional explanations for the narrow sum peaks, the production of a previously unobserved neutral system in the heavy ion collision which subsequently decays to e+e- was considered as a possibility. If such an object were to exist, then it should be possible to produce it through the s-channel of ordinary electron-positron scattering. We describe the results of a set of experiments to search for such a neutral object directly in e+e- collisions