Backward production in π-p→pπ+π-π- at 8 GeV/c*

We have studied backward baryon and meson production in π'p → pπ+pπ +π-π- at 8.0 GeV/c using a streamer chamber triggered by the detection of a fast forward proton. Our data sample (1227 events) displays prominent N*p and N*f quasi-two-body production. These states are investigated with regard to the peripheral nature of the production mechanism and sequential decay of the excited baryon and meson systems. The quasi-two-body production of iV*p and N*f intermediate states is consistent with u -channel proton exchange as the dominant production mechanism. In the π+π-π- mass distribution we observe a 3- to 4- standard-deviation enhancement at M3 w = 1897 ± 17 MeV/c2 with full width at half maximum = 110 ± 82 MeV/c2 , but find no evidence for backward Ax or A2 production. We observe ∆+ +(1232) production in the pπ+ effective mass distribution.