Motivated by the observation of energy- and momentum-correlated e+e- pairs in heavy ion collisions, a search for resonances in e+e- scattering at the corresponding energies has been made. The e+e- decay channel is analyzed in a time window from ∼ 10-13 s to ∼ 10-11 s with a set-up optimized for low-background detection of delayed e+e- decays. The two-photon decay channel of a hypothetical resonance is investigated by measuring the two-photon annihilation-in-flight excitation function. New upper limits for the partial e+e- decay width Γee of a few meV are derived for total centre-of-mass energies √s between 1.78 and 1.92 MeV, taking into account the dilepton as well as the two-photon decay of a neutral resonance.
- 13.10. + q
ASJC Scopus subject areas
- Nuclear and High Energy Physics