Resonances inO16+O16

Abstract

Unambiguous $S$ matrix elements (resonant and background contributions) have been extracted from data on the reaction $^{16}\mathrm{O}$, ($^{16}\mathrm{O}$,${\ensuremath{\alpha}}_{0}$)$^{28}\mathrm{Si}$. Assignments of ${J}^{\ensuremath{\pi}}={10}^{+}, {8}^{+}, \mathrm{and} {8}^{+}$ have been made to resonances at ${E}_{\mathrm{c}.\mathrm{m}.}=15.8, 15.9, \mathrm{and} 16.1$ MeV, respectively: Nonresonant amplitudes result from a narrow angular momentum window about the $l=10$ grazing partial wave; at 90\ifmmode^\circ\else\textdegree\fi{} these dominate the reaction. Systematic behavior of the ${8}^{+}$ resonances in this and other heavy-ion systems suggest that they may not be of binary character and that $\ensuremath{\alpha}$-particle substructure may play a role.