Isospin Nonconservation in theSi28(d,α1)Al0.23, T=126Reaction

The isospin-nonconserving reaction ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}(d,{\alpha }_1){}_{}{}^{26}{}_{}{}^{}\mathrm{Al}(0.23, T=1)$ has been investigated at deuteron energies between 12 and 17 MeV. This experiment was prompted by Noble's recent proposal that the direct-nuclear part of the cross section in the isospin-violating ($d,\alpha$) reaction may proceed via an isospin-mixed $2^{+}$ doublet in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$. In the present study we find no evidence for this mechanism; but even at the high bombarding energies, the largest fraction of the isospin-forbidden cross section is due to compound-nucleus processes. This was determined from the strong fluctuations in the excitation functions.