Unbound States Of Cl-32 And The S-31(P,Gamma)Cl-32 Reaction Rate

The S-31(p,gamma)Cl-32 reaction is expected to provide the dominant break-out path from the SiP cycle in novae and is important for understanding enrichments of sulfur observed in some nova ejecta. We studied the S-32(He-3,t)Cl-32 charge-exchange reaction to determine properties of proton-unbound levels in Cl-32 that have previously contributed significant uncertainties to the S-31(p,gamma)Cl-32 reaction rate. Measured triton magnetic rigidities were used to determine excitation energies in Cl-32. Proton-branching ratios were obtained by detecting decay protons from unbound Cl-32 states in coincidence with tritons. An improved S-31(p,gamma)Cl-32 reaction rate was calculated including robust statistical and systematic uncertainties.