Energy Dependence of Pion Production by Protons on Nuclei

Abstract

The reactions ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$($p$,${\pi }^{+}$)${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$(g.s.) and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$($p$,${\pi }^{+}$)${}_{}{}^{41}{}_{}{}^{}\mathrm{Ca}$(g.s.) have been studied with proton beams in the energy range 140 to 200 MeV. Angular distributions at several energies, supplemented with fixed-angle cross-section data at several other energies, establish for the first time the energy dependence of these reactions in the near-threshold region.