Multipion Photoproduction at Energies up to 6 BeV

Abstract

The photoproduction of multipion (≥ 3) final states has been studied in a hydrogen bubble chamber exposed to a 4.8-6.0-BeV bremsstrahlung photon beam. We find, in most channels, that the reactions are dominated by the production of resonances. In particular, in the three-prong events we discuss the photo-production of ${\eta }^0$ mesons and associated production of $N^{*++}\mathrm{}\left(1238\right)\mathrm{}$ and ${\rho }^{-}$. In the five- and six-body final states we see the production of $N^{*++}\mathrm{}\left(1238\right)\mathrm{}$ and ${\omega }^0$ mesons. We also discuss a slight enhancement of the $p{\pi }^{+}{\pi }^{+}$ and $n{\pi }^{-}{\pi }^{-}$ system observed at about 1560 MeV.