Título: | Effective proton-neutron interaction near the drip line from unbound states in ²?? ²? F |
Autores: | Fraile Prieto, Luis Mario |
Tipo de documento: | texto impreso |
Editorial: | American Physical Society, 2019-11-08 |
Dimensiones: | application/pdf |
Nota general: | info:eu-repo/semantics/openAccess |
Idiomas: | |
Palabras clave: | Estado = Publicado , Materia = Ciencias: Física: Electricidad , Materia = Ciencias: Física: Electrónica , Materia = Ciencias: Física: Física nuclear , Tipo = Artículo |
Resumen: |
Background: Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. The ²?F nucleus, composed of a deeply bound ? 0d_(5/2) proton and an unbound ?0d_(3/2) neutron on top of an ²?O core, is particularly adapted for this purpose. The coupling of this proton and neutron results in a J^?= 1?? - 4?? multiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. The J^? = 1??, 2??, 4?? bound states have been determined, and only a clear identification of the J^? = 3?? is missing. Purpose: We wish to complete the study of the J^? = 1?? - 4??multiplet in ²?F, by studying the energy and width of the J^? = 3??unbound state. The method was first validated by the study of unbound states in ²?, for which resonances were already observed in a previous experiment. Method: Radioactive beams of ²?Ne and ²?Ne, produced at about 440AMeV by the fragment separator at the GSI facility were used to populate unbound states in ²?F and ²?F via one-proton knockout reactions on a CH? target, located at the object focal point of the R³B/LAND setup. The detection of emitted. ? and neutrons, added to the reconstruction of the momentum vector of the A - 1 nuclei, allowed the determination of the energy of three unbound states in ²?F and two in ²?F. Results: Based on its width and decay properties, the first unbound state in ²?F, at the relative energy of 49(9) keV, is proposed to be a J^? = 1/ 2? arising from a p_(1/2) proton- hole state. In ²?F, the first resonance at 323(33) keV is proposed to be the J^? = 3?? member of the J^? = 1??- 4??multiplet. Energies of observed states in ²??²?F have been compared to calculations using the independent-particle shell model, a phenomenological shell model, and the ab initio valence-space in-medium similarity renormalization group method. Conclusions: The deduced effective proton- neutron interaction is weakened by about 30-40% in comparison to the models, pointing to the need for implementing the role of the continuum in theoretical descriptions or to a wrong determination of the atomic mass of ²?F. |
En línea: | https://eprints.ucm.es/id/eprint/46116/1/FrailePrieto23libre.pdf |
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