Cross section and analyzing power of rvec pp→pnπ+ near threshold

The cross section and analyzing power of the rvec pp→pnπ+ reaction near threshold are estimated in terms of data obtained from the rvec pp→dπ+ and pp→ppπ0 reactions. A simple final state interaction theory is developed which depends weakly upon the form of the pion-production operator and includes some Coulomb corrections. Within the uncertainties of the model and the input data, the approach reproduces well the measured energy dependence of the total cross section and the proton analyzing power at a fixed pion center-of-mass angle of 90 degree, from threshold to Tp=330 MeV. The variation of the differential cross section with pion angle is also very encouraging. copyright 1997 The American Physical Society