Microscopic Description of Fission
for the r-Process in Neutron Star Mergers
J.-F. Lemaître, S. Goriely, S. Hilaire, and N. Dubray
1 Introduction
The fission process represents a key physical quantity of interest in fundamental
nuclear physics as well as in many nuclear applications. In particular, it plays a key
role in nucleosynthesis applications and more specifically in our understanding of
the rapid neutron-capture process, or r-process, called for to explain the origin of
about half of the elements heavier than iron in the Universe [1].
In the now well-documented r-process scenario of neutron star mergers, the
number of free neutrons per seed nuclei can reach a few hundred [1–3]. With such a
neutron richness, heavy fissioning nuclei can be produced. In this case, fission plays
a fundamental role, more particularly by (1) recycling the matter during the neutron
irradiation, (2) shaping the r-abundance distribution in the 110 ≤ A ≤ 170 mass
region at the end of the neutron irradiation, (3) defining the residual production
of some specific heavy stable nuclei, more specifically Pb and Bi, but also the
long-lived cosmochronometers Th and U, and (4) heating the environment through
the energy released and consequently impacting the observed light curve of the
astronomical event [2, 3]. For a review on the role of fission during the r-process
nucleosynthesis in neutron star mergers, see Ref. [4].
More specifically, fission probabilities and fission yields are two key quantities
to predict r-abundance distributions. Fission probabilities and yields for a few thousands nuclei, especially heavy exotic neutron-rich nuclei that cannot be produced
in the laboratory, are needed to determine which nuclei are produced or recycled
J.-F. Lemaître () · S. Goriely
Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, Brussels, Belgium
S. Hilaire · N. Dubray
CEA, DAM, DIF, Arpajon, France
© This is a U.S. government work and not under copyright protection
in the U.S.; foreign copyright protection may apply 2021
J. Escher et al. (eds.), Compound-Nuclear Reactions, Springer Proceedings in
Physics 254, https://doi.org/10.1007/978-3-030-58082-7_36
285
for the r-Process in Neutron Star Mergers
J.-F. Lemaître, S. Goriely, S. Hilaire, and N. Dubray
1 Introduction
The fission process represents a key physical quantity of interest in fundamental
nuclear physics as well as in many nuclear applications. In particular, it plays a key
role in nucleosynthesis applications and more specifically in our understanding of
the rapid neutron-capture process, or r-process, called for to explain the origin of
about half of the elements heavier than iron in the Universe [1].
In the now well-documented r-process scenario of neutron star mergers, the
number of free neutrons per seed nuclei can reach a few hundred [1–3]. With such a
neutron richness, heavy fissioning nuclei can be produced. In this case, fission plays
a fundamental role, more particularly by (1) recycling the matter during the neutron
irradiation, (2) shaping the r-abundance distribution in the 110 ≤ A ≤ 170 mass
region at the end of the neutron irradiation, (3) defining the residual production
of some specific heavy stable nuclei, more specifically Pb and Bi, but also the
long-lived cosmochronometers Th and U, and (4) heating the environment through
the energy released and consequently impacting the observed light curve of the
astronomical event [2, 3]. For a review on the role of fission during the r-process
nucleosynthesis in neutron star mergers, see Ref. [4].
More specifically, fission probabilities and fission yields are two key quantities
to predict r-abundance distributions. Fission probabilities and yields for a few thousands nuclei, especially heavy exotic neutron-rich nuclei that cannot be produced
in the laboratory, are needed to determine which nuclei are produced or recycled
J.-F. Lemaître () · S. Goriely
Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, Brussels, Belgium
S. Hilaire · N. Dubray
CEA, DAM, DIF, Arpajon, France
© This is a U.S. government work and not under copyright protection
in the U.S.; foreign copyright protection may apply 2021
J. Escher et al. (eds.), Compound-Nuclear Reactions, Springer Proceedings in
Physics 254, https://doi.org/10.1007/978-3-030-58082-7_36
285