Al27(p, γ)Si28andAl27(He3, d)Si28to the stretched 11.58 MeV (6−, 0) and 14.36 MeV (6−, 1) levels

We have studied the $E_x=14.36\mathrm{}$ MeV $6^{-}$, $T=1\mathrm{}$ resonance in the ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}(p, \gamma )$ reaction with the result that ${\Gamma }_{p_0}=\Gamma =4.0\mathrm{}\pm 0.2$ keV, from which we infer a (${d_{\frac{5}{2}}}^{-1\mathrm{}}, f_{\frac{7}{2}}$) parentage ${{\delta }_1}^2\approx 0.7$. We also obtain $B\left(M1\mathrm{}\right)=2.8\mathrm{}\pm 0.4 {{\mu }_N}^2 or 0.19\pm 0.03$ of the pure single particle (${d_{\frac{5}{2}}}^{-1\mathrm{}}, f_{\frac{7}{2}}$) value for the $6^{-}$, 1→$6^{-}$, 0 $M1\mathrm{}$ $\gamma$ decay. ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}({}_{}{}^3{}_{}{}^{}\mathrm{He}, d)$ results for stripping to the $6^{-}$, 1 and the $6^{-}$, 0 (11.58 MeV) levels indicate $\frac{S_0\mathrm{}\left(p\right)\mathrm{}}{S_1\mathrm{}\left(p\right)\mathrm{}}=1.1\mathrm{}\pm 0.1$ and hence that the $6^{-}$, 0 level has a (${d_{\frac{5}{2}}}^{-1\mathrm{}}, f_{\frac{7}{2}}$) parentage comparable to the $6^{-}$, 1 level, contrary to inferences based on inelastic proton and pion scattering data. We discuss the hindrance of the $M1\mathrm{}$ decay and the previously measured inelastic electron, proton, and pion excitation strengths relative to the expectations of a one-particle-one-hole model.