Charged-Pion Production in Lithium

This article reports the measurement of charged-pion production cross sections in ${\mathrm{Li}}^6$ and ${\mathrm{Li}}^7$. The measurements were made on 40- and 52-Mev pions emitted at 90° to a proton beam of 242-Mev energy. The results show a higher $\frac{{\pi }^{+}}{{\pi }^{-}}$ ratio for ${\mathrm{Li}}^6$ than for ${\mathrm{Li}}^7$; this observation can be qualitatively explained by the Pauli exclusion principle.