Limits for two-photon and e+e- decay widths of positron-electron scattering resonances for √s=1.78 to 1.92 MeV

E. Widmann, W. Bauer, S. Connell, K. Maier, J. Major, A. Seeger, H. Stoll, F. Bosch

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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.

Original languageEnglish
Pages (from-to)209-218
Number of pages10
JournalZeitschrift für Physik A Hadrons and Nuclei
Issue number2
Publication statusPublished - Jun 1 1991



  • 12.20.Fv
  • 13.10. + q
  • 14.80.Pb

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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