Astrophysical 22Mg(p, γ)23Al reaction rates from asymptotic normalization coefficient of 23Ne→22Ne+n
Abstract
The radionuclide 22Na generates the emission of a characteristic 1.275 MeV $\gamma$?--> -ray. This is a potential astronomical observable, whose occurrence is suspected in classical novae. The $^{22}{{\rm{Mg}}}(p,\,\gamma)^{23}{{\rm{Al}}}$?--> 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) for the virtual decay of $^{23}{{\rm{Ne}}}$?--> $\to$?--> $^{22}{{\rm{Ne}}}$?--> + n were extracted, and determined as $(0.483\pm0.060)$?--> fm-1 and $(9.7\pm2.3)$?--> fm-1 for the ground state and the first excited state from the experimental angular distributions of ${}^{22}{{\rm{Ne}}}(d,\,p){}^{23}{{\rm{Ne}}}$?--> populating the ground state and the first excited state of $^{23}{{\rm{Ne}}}$?--> , respectively. Then, the squared proton ANC of ${}^{23}{{\rm{Al}}}_{\rm{g.s.}}$?--> was obtained as $C_{d5/2}^{2}({}^{23}{{\rm{Al}}})=(2.65\pm0.33)\times10^{3}$?--> fm-1 according to the charge symmetry of the strong interaction. The astrophysical S-factors and reaction rates for the direct capture contribution in ${}^{22}{{\rm{Mg}}}(p,\,\gamma){}^{23}{{\rm{Al}}}$?--> were also presented. Furthermore, the proton width of the first excited state of $^{23}{{\rm{Al}}}$?--> was derived to be $(57\pm14)$?--> eV from the neutron ANC of its mirror state in $^{23}{{\rm{Ne}}}$?--> and used to compute the contribution from the first resonance of $^{23}{{\rm{Al}}}$?--> . This result demonstrates that the direct capture dominates the $^{22}{{\rm{Mg}}}(p,\,\gamma)^{23}{{\rm{Al}}}$?--> reaction at most temperatures of astrophysical relevance for $0.33 \lt T_9 \lt 0.64$?--> . * Supported by the National Key Research and Development Program of China (2016YFA0400502), the National Natural Science Foundation of China (11975316, 11490561, 11535004, 11775013), the Continuous Basic Scientific Research Project (WDJC-2019-13) and the 973 Program (2013CB834406)
- Publication:
-
Chinese Physics C
- Pub Date:
- July 2020
- DOI:
- 10.1088/1674-1137/44/7/074001
- Bibcode:
- 2020ChPhC..44g4001L
- Keywords:
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- classical nova;
- transfer reaction;
- asymptotic normalization coefficient;
- radiative capture;
- 26.30.-k;
- 25.45.Hi;
- 21.10.Jx;
- 25.40.Lw