Production of a positive pion in a collision of a 247 MeV negative pion with a proton

Abstract We have measured the total cross-section σ for the reaction π − p → π − π + n at 74 MeV over the threshold and we have found σ = (60 ± 15) μb. The observed differential distributions in the Dalitz plot have been analysed with Gribov's formula obtaining a 2 − a 0 = −(0.42 ± 0.10) m π −1 .