Resonance structure in the γγ invariant mass spectrum in pC, dC, and dCu interactions

摘要

Along with π ~0 and η mesons, a resonance structure in the invariant mass spectrum of two photons atM _(γγ) = 360 ± 7 ± 9 MeV is observed in dC interactions at momentum 2. 75 GeV/c per nucleon. This resonance structure is not observed in pC collisions at the beam momentum 5. 5 GeV/c. The result obtained in the reaction dC is confirmed by the second experiment carried out on the deuteron beam at momentum 3. 83 GeV/c per nucleon with a copper target. Some other checks of the observed effect are presented.