ISOSPIN SELECTION RULE IN 28SI(D,ALPHA)26AL REACTION

The reaction 28Si(d, α)26Al has been investigated in the energy interval 6.98-11.06 MeV. Excitation functions for the transitions to six levels of 26Al were measured in small energy steps. Average values and fluctuation amplitudes of the differential cross sections have been compared with the predictions of the statistical model. A general agreement has been found for the allowed transitions, while the cross section for the forbidden transition to the 26Al first excited state is smaller by a factor 0.25±0.05 than the calculated value. The hindrance can be interpreted as an effect of the isospin selection rule. A value Γ ≈ 75 keV has been deduced for the coherence width of the allowed" transitions. There is some indication of a smaller width for the α1 transition. © 1968."