Multiple Meson Production in Proton-Proton Collisions at 2.85 Bev

Abstract

Measurements are made on 753 four-prong events obtained by exposing a 20- in liquid hydrogen bubble chamber to 2,85-Bev protons. The partial cross sections observed for multiple meson production reactions are: pp +-(p + p yields p+p+ pi /sup +/+ pi /sup -/),2.67 plus or minus 0.13;pn++-,1.15 plus or minus 0.09; pp +- 0, 0.74 + 0.07; d ++-, 0.06 + 0.02; and four or more meson production, 0.04 plus or minus 0.02 mb. Production of two mesons appears to occur mainly in peripheral collisions with relatively little momentum transfer. In cases of three-meson production, however, the protons are typically deflected at large angles and are more strongly degraded in energy. The 3/2, 3/2 pion- nucleon resonance dominates the interaction; there is some indication that one or both of the T =1/2, pion-nucleon resonances also play a part. The resonance in a T = 0, three-pion state appears to be present in the pp +- 0 reaction, Results are compared with the predictions of the isobaric nucleon model and the statistical model. The cross section for the reaction pi /sup O/ + p yields pi /sup +/+ pi /sup -/ + p is derived using an expression from the one-pionmore » exchange mode. (auth)« less