Isobaric analog impurity from total and differential neutron scattering cross sections of silicon

Abstract

Resonance parameters for four resonances in Si have been obtained by analyzing measured differential neutron scattering cross sections combined with the total neutron cross section in the neutron energy range 1.05-1.40 MeV and applying $R$ --- matrix single channel multilevel theory. The resonance at 1254 keV has been identified as the $s$ --- wave analog resonance in $^{29}\mathrm{Si}$. The identification also takes into account experimental radiative neutron capture data and shell model calculations for the radiative width. Estimates of the isospin mixing matrix elements are given.[NUCLEAR REACTIONS $^{28}\mathrm{Si}(n)$, ($n,n$), ${E}_{n}=1.05\ensuremath{-}1.40$ MeV, measured ${\ensuremath{\sigma}}_{\mathrm{nt}}(E)$, $\ensuremath{\sigma}(E)$, $\ensuremath{\sigma}(E,\ensuremath{\theta})$. $R$ matrix analyses, $^{29}\mathrm{Si}$ deduced resonances, $J$, $\ensuremath{\pi}$, $\ensuremath{\Gamma}$. Isobaric analog isospin impurities.]