Final-state interactions in the high-energy proton-deuteron charge exchange reaction

Abstract

The charge exchange channel of the proton-deuteron break-up reaction pd to npp at 1 GeV is studied in impulse approximation. The final-state interaction in the 1S0 state of the pp subsystem induces a slight asymmetry in the spectator proton angle and a threshold enhancement in the pp effective mass. The 20% of the observed events which have large effective mass may be explained quantitatively by the production of a Delta resonance which is de-excited through a final-state interaction with the spectator nucleon. It is concluded that almost all of the small-angle np charge exchange cross section at this energy involves nucleon spin-flip.