| Texto completo | |
| Autor(es): Mostrar menos - |
Titus, E. R.
;
Ney, E. M.
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Zegers, R. G. T.
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Bazin, D.
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Belarge, J.
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Bender, P. C.
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Brown, B. A.
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Campbell, C. M.
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Elman, B.
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Engel, J.
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Gade, A.
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Gao, B.
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Kwan, E.
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Lipschutz, S.
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Longfellow, B.
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Lunderberg, E.
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Mijatovic, T.
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Noji, S.
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Pereira, J.
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Schmitt, J.
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Sullivan, C.
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Weisshaar, D.
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Zamora, J. C.
Número total de Autores: 23
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| Tipo de documento: | Artigo Científico |
| Fonte: | PHYSICAL REVIEW C; v. 100, n. 4, p. 14-pg., 2019-10-22. |
| Resumo | |
Background: In the late stages of stellar core collapse just prior to core bounce, electron captures on medium-heavy nuclei drive deleptonization. Therefore, simulations require the use of accurate reaction rates. Nuclei with neutron number near N = 50 above atomic number Z = 28 play an important role. Rates presently used in astrophysical simulations rely primarily on a relatively simple single-state approximation. In order to improve the accuracy of the astrophysical simulations, experimental data are needed to test the electron-capture rates and to guide the development of better theoretical models and astrophysical simulations. Purpose: The purpose of the present work was to measure the Gamow-Teller transition strength from Kr-86 to Br-86, to derive the stellar electron-capture rates based on the extracted strengths, and to compare the derived rates with rates based on shell-model and quasiparticle random-phase approximation (QRPA) Gamow-Teller strengths calculations, as well as the single-state approximation. An additional purpose was to test the impact of using improved electron-capture rates on the late evolution of core-collapse supernovae. Method: The Gamow-Teller strengths from Kr-86 were extracted from the Kr-86(t, He-3 + gamma) charge-exchange reaction at 115MeV/u. The electron-capture rates were calculated as a function of stellar density and temperature. Besides the case of Kr-86, the electron-capture rates based on the QRPA calculations were calculated for 78 additional isotopes near N = 50 above Z = 28. The impact of using these rates instead of those based on the single-state approximation is studied in a spherically symmetrical simulation of core collapse just prior to bounce. Results: The derived electron-capture rates on Kr-86 from the experimental Gamow-Teller strength distribution are much smaller than the rates estimated based on the single-state approximation. Rates based on Gamow-Teller strengths estimated in shell-model and QRPA calculations are more accurate. The core-collapse supernova simulation with electron-capture rates based on the QRPA calculations indicate a significant reduction in the deleptonization during the collapse phase. Conclusions: It is important to utilize microscopic theoretical models that are tested by experimental data to constrain and estimate Gamow-Teller strengths and derived electron-capture rates for nuclei near N = 50 that are inputs for astrophysical simulations of core-collapse supernovae and their multimessenger signals, such as the emission of neutrinos and gravitational waves. (AU) | |
| Processo FAPESP: | 18/04965-4 - Estudo da estrutura e reações nucleares induzidas por feixes radioativos usando alvo ativo |
| Beneficiário: | Juan Carlos Zamora Cardona |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |