β-delayed neutron-emission and fission calculations within relativistic quasiparticle random-phase approximation and a statistical model

Scientific paper - Original scientific paper

• Author: Futoshi Minato
• Author: Tomislav Marketin
• Author: Nils Paar
• Author's institution: University of Zagreb; Faculty of Science; (Department of Physics)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract (english)

Background: β-delayed neutron emission and fission are essential in r-process nucleosynthesis. Although the number of experimental studies covering r-process nuclei has recently increased, the uncertainties of β-delayed neutron emission and fission are still large for r-process simulations. Purpose: Our aim is to introduce a theoretical framework for the description of β- delayed neutron-emission and fission rates based on relativistic nuclear energy density-functional and statistical models and investigate their properties throughout the nuclide map. Methods: To obtain β strength functions, the relativistic proton-neutron quasiparticle random-phase approximation is employed. Particle evaporations and fission from highly excited nuclear states are estimated by the Hauser-Feshbach statistical model. β-delayed neutron branching ratios P_n are calculated and compared with experimental data, and the β-delayed fission branching ratio P_f are also assessed by using different fission barrier data. Results: Calculated P n are in a good agreement with the experimental data and the root mean square deviation is comparable to results of preceding works. It is found that energy withdrawal by β-delayed neutron-emission sensitivity varies P_n , especially for nuclei near the neutron drip line. P_f depend sensitively on fission barrier data. It is found that not only the barrier height but also the number of barrier humps is important to evaluate P_f . Conclusions: The framework introduced in this work provides an improved theoretical description of the β-delayed neutron emission and fission. Since P_f as well as P_n depend strongly on fission barrier information, four kinds of fission barrier data are used in this work to allow further sensitivity studies of the r-process nucleosynthesis on the nuclear fission. More studies on fission barrier are highly requested to assess the role of β- delayed fission in the r-process study. A complete set of calculated data for β-delayed neutron emission and fission are summarized as a table in supplemental material for its use in r-process studies as well as to complement a part of nuclear data in which no experimental data are available.

• Keywords (english): β-delayed neutron-emission; fission calculations; quasiparticle random-phase approximation
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Physical Review C
• Numbering: vol. 104, no. 4, 044321
• p-ISSN: 2469-9985
• e-ISSN: 2469-9993
• DOI: https://doi.org/10.1103/PhysRevC.104.044321
• URN:NBN: urn:nbn:hr:217:796525
• Publication: 2021-10-19
• Project: Number: KK.01.1.1.01.0004; Title (croatian): Provedba vrhunskih istraživanja u sklopu Znanstvenog centra izvrsnosti za kvantne i kompleksne sustave te reprezentacije Liejevih algebri; Title (english): Implementation of top research within the Scientific Center of Excellence for Quantum and Complex Systems, and Representations of Lie Algebras; Acronym: QuantiXLie; Leader: Hrvoje Buljan; Jurisdiction: eu; Funding stream: European Regional Development Fund
• Document URL: https://link.aps.org/doi/10.1103/PhysRevC.104.044321
• Type of resource: Text
• Access conditions: Open access
• Public note: © 2021 American Physical Society. Received 23 February 2021; revised 21 July 2021; accepted 23 September 2021; published 19 October 2021.
• Created on: 2024-09-14 17:38:53