P o S ( I N P C 2 0 1 6 ) 1 4 8 Newly Discovered Low Energy Resonances In The 22 Ne ( p , γ ) 23

The neon-sodium cycle of hydrogen burning influences the synthesis of the elements between 20Ne and 27Al in red giant stars, asymptotic giant stars, and novae explosions. In order to reproduce the observed elemental abundances, the cross sections of the reactions involved in the nucleosynthesis process should be accurately known. The 22Ne(p,γ)23Na reaction rate is very uncertain because of a large number of unobserved resonances lying in the Gamow window. A new direct study of 22Ne(p,γ)23Na has been performed at the Laboratory for Underground Nuclear Astrophysics (LUNA) in Gran Sasso using a windowless gas target and two different experimental setups. Three resonances (156.2, 189.5, and 259.7 keV) have been observed for the first time in a direct experiment, using two high-purity germanium detectors. Further investigations have been devoted to the tentative resonances at 71 and 105 keV, using a six-fold, optically segmented BGO detector surrounding the interaction volume. The resulting reaction rate is significantly different from the STARLIB 2013 evaluation at temperatures around 0.1 GK, relevant to nucleosynthesis in asymptotic giant branch stars.