Variation of theS32Compound-Nucleus Width with Energy and Spin

Coherence widths of the compound nucleus ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ were determined from excitation functions of the differential cross section for the reactions ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}(p,\alpha ){}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}({}_{}{}^{16}{}_{}{}^{}\mathrm{O},\alpha ){}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$. The proton-induced reaction provided a lower average spin of the compound nucleus. Excitation functions were measured for ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}(p,\alpha ){}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ from 13.90- to 14.24- and from 26.62- to 30.56-MeV compound-nucleus energy. The average coherence widths were 11 ± 1.2 and 95 ± 15 keV, respectively. For the oxygen-induced reaction, excitation functions were measured from 28.99 to 34.42 MeV with a resulting 73 ± 7-keV coherence width, which is nearly the same as for the lower-spin proton-induced case.