Positive pion production by 149-166 MeV protons on ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$

Angular distributions of the differential cross sections for the reactions ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$($p$,${\pi }^{+}$)${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$(g.s., 0.87 MeV) and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$($p$,${\pi }^{+}$)${}_{}{}^{29}{}_{}{}^{}\mathrm{Si}$(g.s., 1.27, 2.03, 3.07, 3.62 MeV) have been measured at several bombarding energies corresponding to pion center-of-mass energies from 7.2 to 21 MeV. In addition, cross section upper limits were obtained at several angles for transitions to the 2.43 and 4.08 MeV states of ${}_{}{}^{29}{}_{}{}^{}\mathrm{Si}$ at $T_p=149\mathrm{}$ MeV. The systematics of the data are discussed and compared with distorted-wave Born approximation stripping model calculations.

NUCLEAR REACTIONS ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$($p$,${\pi }^{+}$), $E_p=149-166\mathrm{}$ MeV; measured $\frac{d\sigma }{d\Omega \left(\theta \right)}$, $\theta =25-155\mathrm{}°$; comparison with DWBA stripping model calculations.