Spin-parity structure of the (K π) system produced in the reaction K −p → (K −π+)n

Abstract

A spin-parity analysis is presented of the (K − π +) system produced in the reaction K −p → (K − π +)n at 10 and 16 GeV/ c for M(K π) < 1.68 GeV and | t pn| < 0.2 GeV 2. The (K π) system is dominantly produced by pion exchange with absorption, but the contributions of natural parity exchanges are not negligible. In (46 ± 3)% of the cases the (K π) system is in an S-wave state whose mass and phase variation are found to be consistent with a Breit-Wigner resonance with mass value M 0 = 1245 ± 30 MeV and width Λ 0 = 485 ± 80 MeV. Cross sections for the individual J P states are presented for 10 and 16 GeV/ c seperately.