Role of the tensor force in induced fission of 240Pu

TL;DR

This study investigates how the tensor force influences the static and dynamic aspects of 240Pu fission, leading to improved agreement with experimental data in barrier heights, fragment distributions, and energy characteristics.

Contribution

It demonstrates that incorporating the tensor force into nuclear models enhances the accuracy of fission barrier predictions and fragment distribution descriptions for 240Pu.

Findings

Tensor force affects fission barrier height and shape evolution.

Including tensor force improves agreement with experimental fragment distributions.

Tensor force enhances shell gaps and TKE predictions.

Abstract

Results: We find that the tensor force affects the height of fission barriers and the double-humped structure of fission path of 240Pu. On the PES, the fission valley becomes larger in the (Q20, Q30) plane, and the triaxial deformation is suppressed around the outer barrier after considering the tensor force. Incorporating the tensor force into the dynamical process enhances the difference in shape evolution between two asymmetric channels. More interestingly, the charge distribution from TDHF with double PNP calculations shows a strong odd-even effect after including the tensor force. In addition, the total mass and charge distributions of fission fragments show a slight shift towards larger asymmetry and are more consistent with the experiments when tensor components are included. We also find that the tensor force enhances energy gaps of the deformed shells for heavy fragments. Moreover, the TKEs of fragments are in accord with the experiments, and after incorporating the tensor force, we observe a higher concentration of the calculated TKEs for heavy fragments at Z = 52 and Z = 56. Conclusions: The tensor force plays a role in both static and dynamical processes in nuclear fission, improving the accuracy of theoretical descriptions within the current framework. Our calculations have shown that the fission-barrier height with SLy5t is closer to the empirical value than that of SLy5. Additionally, the inclusion of the tensor force not only manifests the odd-even effect in charge distribution but also improves the description of total mass and charge distributions.