Astrophysical 22Mg(p,γ)23Al reaction rates from asymptotic normalization coefficient of 23Ne→22Ne+n

The radionuclide 22Na generates the emission of a characteristic 1.275 MeVγ-ray.This is a potential astronomical observable,whose occurrence is suspected in classical novae.The 22Mg(p,γ)23Al reaction is relevant to the nucleosynthesis of 22Na in Ne-rich novae.In this study,employing the adiabatic distorted wave approximation and continuum discretized coupled channel methods,the squared neutron asymptotic normalization coefficients(ANCs)231 for the virtual decay of Ne→22Ne+n were extracted,and determined as(0.483±0.060)fm-1 and(9.7±2.3)fm-1 for the ground state and the first excited state from the experimental angular distributions of 22Ne(d,p)23Ne populating the ground state and the first excited state of 23Ne,respectively.Then,the squared proton ANC of 23Alg.s.was obtained as Cd5/22(23Al)(2.65±0.33)×103 fm-1 according to the charge symmetry of the strong interaction.The astrophysical S-factors and reaction rates for the direct capture contribution in 22Mg(p,γ)23Al were also presented.Furthermore,the proton width of the first excited state of 23Al was derived to be(57±14)eV from the neutron ANC of its mirror state in 23Ne and used to compute the contribution from the first resonance of 23Al.This result demonstrates that the direct capture dominates the 22Mg(p,γ)23Al reaction at most temperatures of astrophysical relevance for 0.33<T9<0.64.

Radii of the bound states in 16N from the asymptotic normalization coefficients

The asymptotic normalization coefficients （ANCs） of the virtual decay 16N -- 15N ＋ n are extracted from the 15N（7Li, 6Li）16N reaction populating the ground and first three excited states in 16N. The root-mean-square （rms） radii of the valence neutron in these four low-lying 16N states are then derived by using the ANCs. The probabilities of the valence neutron staying out of the core potentials are found to be 31%± 8%, 58%± 12%, 3270 ± 8%, and 60% ± 12%. The present results support the conclusion that a one-neutron halo may be formed in the 16N first and third excited states, while the ground and second excited states do not have a one-neutron halo structure. However, the core excitation effect has a strong influence on the one-neutron halo structure of the ground and first excited states in 16N.