Inelastic π −-nucleon interactions at 6.8 GeV in the bubble chamber

Abstract

Bubble chamber pictures taken from the 24 1 propane bubble chamber of the Joint Institute for Nuclear Research (Dubna) exposed to negative pions of (6.8±0.6) GeV/ c momentum were scanned for inelastic pion-nucleon interactions. A total of 171 inelastic π −-nucleon events has been found. The distributions of momenta, angles and transverse momenta are given. The results are compared with those of inelastic pion-nucleon interactions in nuclear emulsions. It is found that about 20% of the interactions identified in the propane bubble chamber are actually events which in nuclear emulsion would not show up as pion-nucleon collisions. From an investigation of the accidental and systematic errors in the momentum determination it is concluded that distortions in the bubble chamber and on the photographic film cannot be neglected if high momenta are measured.