Abstract
The 31S(p,g )32Cl proton–capture reaction is expected to be the dominant breakout pathway of the
SiP cycle, which is important for understanding nucleosynthesis in some novae [1]. At novae
temperatures, the 31S(p,g )32Cl reaction rate is dominated by 31S+p resonances. Discrepancies
in the 32Cl resonance energies were reported in previous measurements [1, 2]. We used the
32S(3He,t)32Cl charge–exchange reaction to produce unbound states in 32Cl and determine their
excitation energies by detecting tritons at the focal plane of the Enge Spectrograph at the Yale
University’s Wright Nuclear Structure Laboratory. Proton branching ratios were determined by
detecting the decay protons coming from the residual 32Cl states using a silicon array in the
spectrometer’s target chamber. The improved energy values of excited levels in 32Cl and measurements
of the proton-branching ratios should significantly improve our understanding of the
31S(p,g )32Cl reaction rate.
