Pion production cross sections and analyzing powers in the inclusiveC12(p,π+)X reaction at 400 and 450 MeV

Inclusive differential cross sections and analyzing powers of the (p,${\pi }^{+}$) reaction on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ have been obtained at 400 and 450 MeV incident proton energies. The energy domain investigated spans the region of pion energies that arise in the pp→d${\pi }^{+}$ reaction, a reaction which was measured at the same time. A 65 cm Browne-Buechner spectrometer, in a single-arm configuration, was used for detecting the pions. Measurements were made in the angular range of 46°–88° (lab). At forward angles the measured analyzing powers in the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(p,${\pi }^{+}$)X reaction are quantitively similar to those of the pp→d${\pi }^{+}$ and pp→pn${\pi }^{+}$ reactions, but at backward angles they are considerably more negative. The analyzing power data for angles ≲70° (lab) are consistent with the predictions of a simple quasifree model that incorporates the free pN→NN${\pi }^{+}$ data. Moreover, this model makes a reasonable prediction of the overall strength of the differential cross sections and also reproduces the qualitative shape of the pion energy distributions.