Clustering and α -capture reaction rate from ab initio symmetry-adapted descriptions of Ne20
| Autor: | Jutta Escher, Tomas Dytrych, Grigor Sargsyan, A C Dreyfuss, Kristina D. Launey, R. B. Baker, Jerry P. Draayer |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Physical Review C. 102 |
| ISSN: | 2469-9993 2469-9985 |
| DOI: | 10.1103/physrevc.102.044608 |
| Popis: | We introduce a new framework for studying clustering and for calculating alpha partial widths using ab initio wave functions. We demonstrate the formalism for $^{20}$Ne, by calculating the overlap between the $^{16}$O$+\alpha$ cluster configuration and states in $^{20}$Ne computed in the ab initio symmetry-adapted no-core shell model. We present spectroscopic amplitudes and spectroscopic factors, and compare those to no-core symplectic shell-model results in larger model spaces, to gain insight into the underlying physics that drives alpha-clustering. Specifically, we report on the alpha partial width of the lowest $1^-$ resonance in $^{20}$Ne, which is found to be in good agreement with experiment. We also present first no-core shell-model estimates for asymptotic normalization coefficients for the ground state, as well as for the first excited $4^{+}$ state in $^{20}$Ne that lies in a close proximity to the $^{16}$O$+\alpha$ threshold. This outcome highlights the importance of correlations for developing cluster structures and for describing alpha widths. The widths can then be used to calculate alpha-capture reaction rates for narrow resonances of interest to astrophysics. We explore the reaction rate for the alpha-capture reaction $^{16}$O$(\alpha,\gamma)^{20}$Ne at astrophysically relevant temperatures and determine its impact on simulated X-ray burst abundances. |
| Databáze: | OpenAIRE |
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