Examination of the ground-state transitions of the ($p,t$) and ($p,{}_{}{}^3{}_{}{}^{}\mathrm{He}$) reactions on all $T_z=\frac{1}{2}$ nuclei from ${}_{}{}^{21}{}_{}{}^{}\mathrm{Ne}$ through ${}_{}{}^{39}{}_{}{}^{}\mathrm{K}$ reveals a systematic suppression of the $S=1\mathrm{}$, $T=0\mathrm{}$ component of the ($p,{}_{}{}^3{}_{}{}^{}\mathrm{He}$) transfer cross sections which is not explained in terms of current structure and reaction theories.

• Received 14 June 1976

DOI:https://doi.org/10.1103/PhysRevLett.37.1129