Future of nuclear fission theory

There has been much recent interest in nuclear fission, due in part to a new appreciation of its relevance to astrophysics, stability of superheavy elements, and fundamental theory of neutrino interactions. At the same time, there have been important developments on a conceptual and computational level for the theory. The promising new theoretical avenues were the subject of a workshop held at the University of York in October 2019; this report summarises its findings and recommendations.ASU and CS would like to thank Prof. David Hinde for useful discussions regarding the neutron clock. This work was partially supported by the STFC Grant Nos. ST/M006433/1, ST/P003885/1, and ST/P005314/1, by the Polish National Science Centre under Contract Nos. 2018/31/B/ST2/02220, 2018/30/Q/ST2/00185, and 2017/27/B/ST2/02792; by JSPS KAKENHI Grant Number JP19K03861; by the National Natural Science Foundation of China under Grant Nos. 11875225 and 11790325; by the U.S. Department of Energy under Grant Nos. DE-SC0013847, DE-SC0019521, DE-SC0013365, DE-SC0018083, DE-NA0003885, and DE-SC0019521; by Spanish Ministry of Economy and Competitiveness (MINECO) Grant No. PGC2018-094583-B-I00; by the Fonds de la Recherche Scientifique (F.R.S.-FNRS) and the Fonds Wetenschappelijk Onderzoek—Vlaanderen (FWO) under the EOS Project nr O022818F; and by the Australian Research Council Grant No. DP190100256. This work was partly performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 (NS). The work was also supported by the US Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of U.S. Department of Energy (Contract No. 89233218CNA000001). This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 654002. JR wishes to acknowledge the Yukawa Institute for Theoretical Physics in Kyoto for its generous support of his participation is this project

Future of nuclear fission theory

There has been much recent interest in nuclear fission, due in part to a new appreciation of its relevance to astrophysics, stability of superheavy elements, and fundamental theory of neutrino interactions. At the same time, there have been important developments on a conceptual and computational level for the theory. The promising new theoretical avenues were the subject of a workshop held at the University of York in October 2019; this report summarises its findings and recommendations.Peer reviewe

Towards more accurate and reliable predictions for nuclear applications

The need for nuclear data far from the valley of stability, for applications such as nuclear astrophysics or future nuclear facilities, challenges the robustness as well as the predictive power of present nuclear models. Most of the nuclear data evaluation and prediction are still performed on the basis of phenomenological nuclear models. For the last decades, important progress has been achieved in fundamental nuclear physics, making it now feasible to use more reliable, but also more complex microscopic or semi-microscopic models in the evaluation and prediction of nuclear data for practical applications. Nowadays mean-field models can be tuned at the same level of accuracy as the phenomenological models, renormalized on experimental data if needed, and therefore can replace the phenomenological inputs in the evaluation of nuclear data. The latest achievements to determine nuclear masses within the non-relativistic HFB approach, including the related uncertainties in the model predictions, are discussed. Similarly, recent efforts to determine fission observables within the mean-field approach are described and compared with more traditional existing models

Towards more accurate and reliable predictions for nuclear applications

The need for nuclear data far from the valley of stability, for applications such as nuclear astrophysics or future nuclear facilities, challenges the robustness as well as the predictive power of present nuclear models. Most of the nuclear data evaluation and prediction are still performed on the basis of phenomenological nuclear models. For the last decades, important progress has been achieved in fundamental nuclear physics, making it now feasible to use more reliable, but also more complex microscopic or semi-microscopic models in the evaluation and prediction of nuclear data for practical applications. Nowadays mean-field models can be tuned at the same level of accuracy as the phenomenological models, renormalized on experimental data if needed, and therefore can replace the phenomenological inputs in the evaluation of nuclear data. The latest achievements to determine nuclear masses within the non-relativistic HFB approach, including the related uncertainties in the model predictions, are discussed. Similarly, recent efforts to determine fission observables within the mean-field approach are described and compared with more traditional existing models.SCOPUS: cp.pinfo:eu-repo/semantics/publishe

Microscopic Description of Fission for the r-Process in Neutron Star Mergers

Fission barriers for a large number of nuclei have been extracted from Gogny D1M potential energy surfaces and compared to experimental data. The same data have been used to estimate spontaneous fission half-lives on the basis of the least-action path. An upgraded version of the SPY model for the calculation of the main observables related to fission fragments is also presented. Fission path and yields are key ingredients to estimate the composition of matter synthesized by the r-process nucleosynthesis in the ejecta of binary neutron star mergers.SCOPUS: cp.pinfo:eu-repo/semantics/publishe

SPY: A new scission point model based on microscopic ingredients to predict fission fragments properties

info:eu-repo/semantics/publishe

SPY: a new scission-point model based on microscopic inputs to predict fission fragment properties

info:eu-repo/semantics/publishe

New statistical scission-point model to predict fission fragment observables

info:eu-repo/semantics/publishe

New fission fragment distributions and r-process origin of the rare-Earth elements

info:eu-repo/semantics/publishe

The r-process nucleosynthesis during the decompression of neutron star crust material

About half of the nuclei heavier than iron observed in nature are produced by the so-called rapid neutron capture process, or r-process, of nucleosynthesis. The identification of the astrophysics site and the specific conditions in which the r-process takes place remains, however, one of the still-unsolved mysteries of modern astrophysics. Another underlying difficulty associated with our understanding of the r-process concerns the uncertainties in the predictions of nuclear properties for the few thousands exotic neutron-rich nuclei involved, for which essentially no experimental data exist.The present paper emphasizes some important future challenges faced by nuclear physics in this problem, particularly in the determination of the nuclear structure properties of exotic neutron-rich nuclei as well as their radiative neutron capture rates and their fission probabilities. These quantities are particularly relevant to determine the composition of the matter resulting from the r-process. Both the astrophysics and the nuclear physics difficulties are critically reviewed with special attention paid to the r-process taking place during the decompression of neutron star matter following the merging of two neutron stars.SCOPUS: cp.jinfo:eu-repo/semantics/publishedNuclear Physics in Astrophysics VI (NPA6)19–24 May 2013, Lisbon, Portuga