γ-ray constraints on the properties of unbound32Cl levels

Abstract

Systematic differences between measurements of excitation energies and branching ratios of unbound 32 Cl levels near the proton threshold have recently emerged. We investigate these 32 Cl properties using independent information by analyzing existing 32 Ar(βγ) 32 Cl data and using published values from measurements of the 32 S( 3 He,tγ) 32 Cl reaction. Significant evidence emerges in support of particular values. The results increase the thermonuclear rate of the 31 S(p, γ) 32 Cl reaction by up to a factor of two over the temperature range of 0.4 to 2 GK that is reached during type I x-ray bursts on hydrogen-accreting neutron stars.

γ spectroscopy of states in Cl32 relevant for the S31Afanasieva1, Blackmon2, Deibel3 et al. 2017Phys. Rev. C0000View full textAdd to dashboardCite

“…[8]). Gamma-ray branching ratio measurements for the 628-and 702-keV states indicate that the proton branching ratios (Γ p /Γ) are approximately 1 [9]. This is supported by neutron spectroscopic factors from the mirror states, which indicate that proton partial widths are expected to be about 25-30 times larger than the γ partial widths for these levels.…”

“…[1] and [8]. A precise value for the energy of the 2209-keV level was also determined following 32 Ar β + decay [9][10][11]. Previous results for excitation energies in 32 Cl are summarized in Table I.…”