New concept for pairing anti-halo effect as a localized wave packet of quasi-particle

TL;DR

This paper introduces a new intuitive concept of the pairing anti-halo effect as a localized wave packet of a quasi-particle, using a three-body model to provide deeper insight into nuclear radius suppression.

Contribution

It presents a novel three-body model approach that conceptualizes the pairing anti-halo effect as a localized wave packet, bridging it with the HFB theory.

Findings

The anti-halo effect can be described by a localized quasi-particle wave packet.

The model expresses one-particle density in terms of quasi-particle wave functions.

The approach offers an intuitive understanding of the pairing anti-halo phenomenon.

Abstract

The pairing anti-halo effect is a phenomenon that a pairing correlation suppresses a divergence of nuclear radius, which happens for single-particle states with orbital angular momenta of $l$ = 0 and 1 in the limit of vanishing binding energy. While this effect has mainly been discussed in terms of Hartree-Fock-Bogoliubov (HFB) theory, we here use a three-body model and provide its new intuitive concept as a localized wave packet for a quasi-particle, that is, a coherent superposition of a weakly bound and continuum wave functions due to a pairing interaction. We show that the one-particle density in the three-body model can be directly expressed with such quasi-particle wave functions, which have a close analog to wave functions in the HFB approximation.