Doorway States and Background Cross Sections inSi29(γ,n)

Abstract

A study of the reaction $^{29}\mathrm{Si}(\ensuremath{\gamma},n)$ near threshold suggests that a doorway state with ${J}^{\ensuremath{\pi}}={\frac{3}{2}}^{\ensuremath{-}}$ common to the channels $^{28}\mathrm{Si}+n$ and $^{29}\mathrm{Si}+\ensuremath{\gamma}$ lies near 750 keV. We observe experimentally Lane's prediction of a significant nonresonant background cross section associated with strong partial-width correlations.