Strong Polarization of the1p-Shell Core in the LowestO+States ofMg24andSi28

Abstract

Inelastic $\alpha$ scattering to the first excited ${\mathrm{O}}^{+}$ states in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ has been measured at $E_{\alpha }=23.5\mathrm{}$ MeV and analyzed in a microscopic model. Strong evidence for the need of including $1p_{\frac{1}{2}}$ hole components in the wave functions of the lowest ${\mathrm{O}}^{+}$ states was found. Deduced $E0\mathrm{}$ matrix elements are in surprisingly good agreement with results from electron scattering.