Detailed comparison of the pp -> π^+pn and pp -> π^+d reactions at 951 MeV

GEM collaboration; M. Abdel-Bary

doi:10.1016/j.physletb.2005.01.100

paper

Detailed comparison of the pp -> π^+pn and pp -> π^+d reactions at 951 MeV

arXiv:nucl-ex/0412002 · doi:10.1016/j.physletb.2005.01.100

Abstract

The positively charged pions produced in proton-proton collisions at a beam momentum of 1640 MeV/c were measured in the forward direction with a high resolution magnetic spectrograph. The missing mass distribution shows the bound state (deuteron) clearly separated from the $p n$ continuum. Despite the very good resolution, there is no evidence for any significant production of the $p n$ system in the spin-singlet state. However, the $σ (pp \to π^{+} p n) / σ (pp \to π^{+} d)$ cross section ratio is about twice as large as that predicted from $S$ -wave final-state-interaction theory and it is suggested that this is due to $D$ -state effects in the $p n$ system.

8 pages, 3 figures