πp phase shifts from 88 to 310 MeV

Abstract

Phase shift solutions are presented at pion kinetic energies from 88 to 292 MeV where new measurements of the differential elastic cross section are available, and at 310 MeV. The resulting phase shifts are fitted to effective-range formulae. The resonant P 33 phase shift is allowed to take different values for π +p and π −p scattering. There are differences in mass and width between these charge states of the resonance of M 0 − M ++ = 1.4 ± 0.4 MeV/ c 2 and Γ 0 − Γ ++ = 10.3 ± 1.3 MeV/ c 2. The difference in width can be accounted for largely but not entirely by the Coulomb barrier, the channel π −p → γn, and the difference in phase space between π −p → π 0n and π +p → π +p.