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Nucleon self-energies for supernova equations of state

Hempel, M.. (2015) Nucleon self-energies for supernova equations of state. Physical Review C - Nuclear Physics , 91 (5). 055807.

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Official URL: http://edoc.unibas.ch/41646/

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Abstract

Nucleon self-energies and interaction potentials in supernova (SN) matter, which are known to have an important effect on nucleosynthesis conditions in SN ejecta are investigated. Corresponding weak charged-current interaction rates with unbound nucleons that are consistent with existing SN equations of state (EOSs) are specified. The nucleon self-energies are made available online as electronic tables. The discussion is mostly restricted to relativistic mean-field models. In the first part of the article, the generic properties of this class of models at finite temperature and asymmetry are studied. It is found that the quadratic expansion of the EOS in terms of asymmetry works reasonably well at finite temperatures and deviations originate mostly from the kinetic part. The interaction part of the symmetry energy is found to be almost temperature independent. At low densities, the account of realistic nucleon masses requires the introduction of a linear term in the expansion. Finally, it is shown that the important neutron-to-proton potential difference is given approximately by the asymmetry of the system and the interaction part of the zero-temperature symmetry energy. The results of different interactions are then compared with constraints from nuclear experiments and thereby the possible range of the potential difference is limited. In the second part, for a certain class of SN EOS models, the formation of nuclei is considered. Only moderate modifications are found for the self-energies of unbound nucleons that enter the weak charged-current interaction rates. This is because in the present approach the binding energies of bound states do not contribute to the single-particle energies of unbound nucleons.
Faculties and Departments:05 Faculty of Science > Departement Physik > Physik > Theoretische Physik Astrophysik (Thielemann)
UniBasel Contributors:Hempel, Matthias
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:American Physical Society
ISSN:0556-2813
e-ISSN:1089-490X
Note:Publication type according to Uni Basel Research Database: Journal article
Language:English
Identification Number:
Last Modified:22 Feb 2017 13:10
Deposited On:19 May 2016 06:44

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