Inhibited (He3,d) Transitions to3s12Isobaric Analog States

The (${}_{}{}^3{}_{}{}^{}\mathrm{He},d$), reaction cross sections on ${}_{}{}^{90,92,94}{}_{}{}^{}\mathrm{Zr}$ and ${}_{}{}^{92,94,96,98}{}_{}{}^{}\mathrm{Mo}$ targets have been measured to unbound isobaric analog states. All expected transitions are observed except those to $3s_{\frac{1}{2}}$ analog states which are inhibited. Distorted-wave Born approximation calculations do not explain the anomaly. Other possible explanations are suggested.