Production Cross Sections forπ+- andπ−-Mesons by 340-Mev Protons on Carbon and Lead at 90° to the Beam

Abstract

Carbon and lead targets were bombarded by 340-Mev protons produced by the Berkeley 184-inch synchrocyclotron. The spectrum of ${\pi }^{+}$- and ${\pi }^{+}$-mesons produced at 90°±12° to the beam was measured by the use of nuclear emulsions embedded in absorbers. The total cross section for the production of ${\pi }^{+}$-mesons from carbon at this angle is (2.3±0.5)·${10}^{-28\mathrm{}}$ ${\mathrm{cm}}^2$ ${\mathrm{ster}}^{-1\mathrm{}}$, and the ${\pi }^{+}$ to ${\pi }^{-}$ ratio is 5.1±1.0. For lead the cross section for ${\pi }^{+}$-mesons at this angle is (7±2.1)·${10}^{-28\mathrm{}}$ ${\mathrm{cm}}^2$ ${\mathrm{ster}}^{-1\mathrm{}}$ and the ${\pi }^{+}$ to ${\pi }^{-}$ ratio is 1.5±0.4.