Fission of heavy $\Lambda$ hypernuclei with the Skyrme-Hartree-Fock approach

TL;DR

This paper investigates how the presence of a $ ext{Lambda}$ hyperon affects the fission properties of heavy hypernuclei using the Skyrme-Hartree-Fock+BCS method, revealing slight increases in fission barrier heights and potential for producing neutron-rich hypernuclei.

Contribution

It introduces a novel application of the Skyrme-Hartree-Fock+BCS approach to study fission in hypernuclei, highlighting the impact of $ ext{Lambda}$ particle placement on fission barriers and fragment attachment.

Findings

Fission barrier height slightly increases with $ ext{Lambda}$ in the lowest level.

The $ ext{Lambda}$ particle tends to attach to the heavier fission fragment.

Potential for producing neutron-rich $ ext{Lambda}$ hypernuclei through fission.

Abstract

Fission-related phenomena of heavy $\Lambda$ hypernuclei are discussed with the constraint Skyrme-Hartree-Fock+BCS (SHF+BCS) method, in which a similar Skyrme-type interaction is employed also for the interaction between a $\Lambda$ particle and a nucleon. Assuming that the $\Lambda$ particle adiabatically follows the fission motion, we discuss the fission barrier height of $^{239}_{\Lambda}$U. We find that the fission barrier height increases slightly when the $\Lambda$ particle occupies the lowest level. In this case, the $\Lambda$ particle is always attached to the heavier fission fragment. This indicates that one may produce heavy neutron-rich $\Lambda$ hypernuclei through fission, whose weak decay is helpful for the nuclear transmutation of long-lived fission products. We also discuss cases where the $\Lambda$ particle occupies a higher single-particle level.