Backward production inπ−p→pπ+π−<

Abstract

We have studied backward baryon and meson production in T-p -+p?rf T-?r-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 N*p and N* f intermediate states is consistent with u-channel proton exchange as the dominant production mechanism. In the ~' a -amass distribution we observe a 3-to 4standard-deviation enhancement at M3, = 1897 * 17 M e V / c 2 with full width at half maximum = 110 * 82 MeV/c ,, but find no evidence for backward A, or A, production. We observe Af+(1232) production in the p~+ effective mass distribution.