New energy for the 133-keV resonance in the 23Na(p ,γ )24Mg reaction and its impact on nucleosynthesis in globular clusters

Globular cluster stars exhibit star-to-star anticorrelations between oxygen and sodium in their atmospheres. An improved description of the sodium-destroying ²³Na+p reaction rates is essential to understanding these observations. We present an energy analysis of ²⁴Mg states based on a new measurement of the ²³Na(³He,d )²⁴Mg reaction. A key resonance in ²³Na(p ,γ )²⁴Mg is found to be at E_r^c.m.=133 (3 ) keV, 5 keV lower than previously adopted. This finding has a dramatic effect on the ²³Na(p ,γ )²⁴Mg reaction rate, increasing it by a factor of 2 for the recommended rate. The nucleosynthesis impact of this change is investigated.