Deformed neutron halo nuclei and soft dipole excitations in the 40<A<90 mass region

TL;DR

This paper investigates deformed neutron halo nuclei in the 40<A<90 mass region using the deformed relativistic Hartree-Bogoliubov theory, highlighting the role of soft dipole excitations in identifying halo features.

Contribution

It introduces a detailed analysis of deformed halo nuclei and their dipole responses, emphasizing the sensitivity of dipole strength to halo configurations and deformation.

Findings

Identification of unique density features in halo nuclei influenced by high-l configurations.

Dipole response as a sensitive probe for halo components and nuclear deformation.

Call for experimental validation of low-energy dipole strength to confirm deformed halo candidates.

Abstract

We study deformed neutron halo nuclei in the mass region $40 < A < 90$ and their soft electric dipole ($E1$) excitations based on the deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). Three candidates, $^{43}$Si, $^{69}$Ti, and $^{75}$Cr, are selected for detailed analysis. Unique features are identified in the decoupled densities of possible $s$- and $p$-wave deformed halo nuclei in this mass region, which are influenced by large high-$l$ configurations. It is shown that the dipole response is a highly sensitive observable to detect the halo component of the single-particle wave function in deformed halo nucleus, and it helps identify the configuration and the magnitude of deformation for halo nuclei in the $40 < A < 90$ mass region. Experimental confirmation of the dipole strength in the low-energy region is highly desirable to explore possible deformed halo candidates in the medium-heavy mass region.