Low-Energy Resonances and Direct Capture Cross Section in the 22Ne(p},Υ)23Na Reaction

The 22Ne(p,γ)23Na reaction takes part in the neon-sodium (NeNa) cycle of hydrogen burning. The 22Ne(p,γ)23Na reaction rate was the most uncertain in the NeNa cycle because of a large number of uncertain resonances in the Gamow window. A new direct study of the 22Ne(p,γ)23Na reaction has been completed at the Laboratory for Underground Nuclear Astrophysics (LUNA), using a windowless gas target and two complementary setups. Three new resonances at 156.2, 189.5 and 259.7 keV have been discovered and their decay scheme has been determined both with a high-resolution setup and with a high-efficiency one. Improved upper limits have been put for the tentative resonances at 71 and 105 keV, making their contribution to the thermonuclear reaction rate almost irrelevant. The high-efficiency setup allowed the measurement of the non-resonant cross section at unprecedentedly low energies.