Sensitive search for resonances in low-energy e+e- scattering.

We have searched for resonances in {ital e}{sup +}{ital e{minus}} scattering in a range of positron kinetic energies from 1.9 to 2.5 MeV (1.75--1.88 MeV invariant energy). Such resonances would exist if the anomalous electron-positron pairs observed in heavy-ion collisions were due to two-body decay of a neutral object. Our 97% confidence limit excludes resonances with an energy-integrated cross section greater than 0.3 to 2.4 b eV/sr, depending upon the incident positron energy. For scalar resonances, this corresponds to a lower limit of the lifetime that varies from 8{times}10{sup {minus}14} to 5{times}10{sup {minus}13} sec. These are the most sensitive limits to date.