Predicting reaction observables for the two-neutron halo candidates $^{31}$F and $^{39}$Na

TL;DR

This study combines nuclear structure models with reaction simulations to predict observables for two-neutron halo candidates $^{31}$F and $^{39}$Na, confirming their halo nature and suggesting new candidates.

Contribution

First microscopic description of $^{31}$F and $^{39}$Na as two-neutron halo candidates using combined structure and reaction models.

Findings

Reaction cross sections match experimental data.

Pronounced increase in RCS for specific isotopes.

Narrow momentum distributions confirm halo structure.

Abstract

Microscopic description of two-neutron ($2n$) halo candidates $^{31}$F and $^{39}$Na has been realized from nuclear structure to reaction observables for the first time. The reliability of the Glauber reaction model has been confirmed by exactly reproducing the momentum distributions of the benchmark $2n$ halo nucleus $^{11}$Li, with the identical structural inputs from the former work. Combined with the structure from the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc), the Glauber model is applied to predict the reaction observables, including the reaction cross sections (RCSs) for the fluorine and sodium isotopes bombarding a carbon target at 240~MeV/A and the longitudinal momentum distributions of the fragments after $2n$ knockout reactions. It turns out that the calculated RCSs agree well with the available experimental data and a pronounced increase occurs to $^{29, 31}$F + $^{12}$C and $^{37, 39}$Na + $^{12}$C, which deviate from the original trend of their neighbours. Furthermore, the narrower longitudinal momentum distributions of the fragments after $2n$ knockout reactions demonstrate that $^{31}$F and $^{39}$Na have the dilute $2n$ halo structure. Such a new combination is promising to suggest new $2n$ halo candidates for future measurements.