Single-pion production in pn collisions at 11.6 GeV/ c

Abstract

The process pn → pp π − is studied in pd collisions at 11.6 GeV/ c. A broad low-mass enhancement of p π − is found in the diffractive reaction pn → p(p π −) with a cross section slightly smaller than that of a similar analysis at 7.0 GeV/ c. The non-diffractive reaction pn → (p π −)p shows some evidence for resonance production and its cross-section dependence on energy is characteristic of meson exchange. Samples of mass, momentum transfer, and decay angular distributions are compared with the predictions of a double Regge model and a reggeized one-pion exchange model. Using in addition information from the reactions pp → pp π 0, pp → pn π + at 12.0 GeV/ c, an isospin analysis of the single pion production reaction from nucleon-nucleon scattering, N 1N 2 → N 3(N 4 π) is presented.