A new analysis of K π scattering as observed in [formula omitted] from 3 to 13 GeV/ c

Abstract

K π scattering is studied in 77 300 bubble chamber events of K +p→K + π − π +p and 18800 events of K +p→K o π o π +pfor beam momenta between 2.5 and 12.7 GeV/ c. The on-shell moments of the angular distribution and the cross sections for K + π −→K + π −, K + π − →K 0 π 0 and K + π o →K o π + are obtained by extrapolation to the pion pole. The same procedure applied to the π +p system correctly reproduces the known π +p scattering. A Kπ phase shift analysis between threshold and 1.1 GeV yields two solutions for the S wave isospin 1 2 phase shift ( δ 0 1). One solution gives a slowly increasing δ 0 1 which approaches about 70° at 1.1 GeV. The other solution superposes on this behaviour a relatively narrow (⪅ 30 MeV) resonant δ 0 1 state near 890 MeV. Either case is compatible with a resonance in δ 1 1 near 895 MeV and with a small, negative δ 0 3.