Proton Decay from Isobaric Analog States Formed in the (d, n) Reactions

A study of the cross sections of proton decay of isobaric analog states formed in the ($d, n$) reaction has been made with a variety of medium mass targets. Particular attention is paid to the large variation in cross sections for reactions which proceed through the analogs of $d_{\frac{5}{2}}$, $s_{\frac{1}{2}}$, and $d_{\frac{3}{2}}$ states in the Zr, Mo, and Sn isotopes. At energies ($E_{\mathrm{inc}}\sim 16$ MeV) far above threshold this variation is shown to be consistent with a sequential process in which the ($d, n$) formation mechanism is direct. The cross sections to the target ground states are large only when the neutron decay channels are closed.