Structure in Neutron-Proton Charge Exchange

Abstract

Neutron-proton charge-exchange differential cross sections for incident-neutron momenta between 600 and 2000 MeV/c show a sharp change in the slope of $\frac{d\ensuremath{\sigma}}{\mathrm{dt}}$ vs -$u$ in the vicinity of $\ensuremath{-}u=0.01$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{2}$. Near the one-pion threshold the slope at $u=0$ shows a maximum which reaches a value of order 100 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^{\ensuremath{-}2}$. Also presented, as a function of $s$, is the intercept at $u=0$ which shows a pronounced deviation from smoothness in the region above the inelastic threshold.