Energetic charged particle yields induced by pions on complex nuclei

Abstract

The spectra of protons ($60<{E}_{p}<200$ MeV) and deuterons ($80 \mathrm{MeV}<{E}_{d}$) produced by 100- and 220-MeV ${\ensuremath{\pi}}^{+}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}$ on Al, Ni, and Ta targets were measured. The shapes of proton spectra are similar for ${\ensuremath{\pi}}^{+}$ and ${\ensuremath{\pi}}^{\ensuremath{-}}$, with absolute yields in \ensuremath{\sim}3:1 ratio; the yields vary as $\ensuremath{\sim}{A}^{\frac{2}{3}}$. The exception is the forward-angle yield at 100 MeV where the proton spectra with ${\ensuremath{\pi}}^{+}$ are different in shape from ${\ensuremath{\pi}}^{\ensuremath{-}}$, the yield \ensuremath{\sim}5 times as high, and the target dependence is $\ensuremath{\sim}{A}^{\frac{1}{3}}$. This pattern is not readily understood at the present time.NUCLEAR REACTIONS $^{27}\mathrm{Al}$, $^{62}\mathrm{Ni}$, $^{181}\mathrm{Ta}$, (${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}},p$), and (${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}},d$). ${E}_{\ensuremath{\pi}}=100, 220$ MeV, $\ensuremath{\theta}=45, 94\ifmmode^\circ\else\textdegree\fi{}$; measured $\frac{{d}^{2}\ensuremath{\sigma}}{d\ensuremath{\Omega}\mathrm{dE}}$ for $50<{E}_{p}<200$ MeV and $80<{E}_{d}<200$ MeV.