Na23(α,p)Mg26Reaction Rate at Astrophysically Relevant Energies

The production of Al-26 in massive stars is sensitive to the Na-23(alpha, p)Mg-26 cross section. Recent experimental data suggest the currently recommended cross sections are underestimated by a factor of similar to 40. We present here differential cross sections for the Na-23(alpha, p)Mg-26 reaction measured in the energy range E-c.m. = 1.7-2.5 MeV. Concurrent measurements of Rutherford scattering provide absolute normalizations that are independent of variations in target properties. Angular distributions are measured for both p(0) and p(1) permitting the determination of total cross sections. The results show no significant deviation from the statistical model calculations upon which the recommended rates are based. We therefore retain the previous recommendation without the increase in cross section and resulting stellar reaction rates by a factor of 40, impacting the Al-26 yield from massive stars by more than a factor of 3.