Roles of the tensor and pairing correlations on the halo formation in 11Li

TL;DR

This paper investigates how tensor and pairing correlations influence the formation of the neutron halo in 11Li using an extended shell model that accounts for these correlations and Pauli-blocking effects.

Contribution

It introduces a comprehensive model that incorporates tensor and pairing correlations in 11Li, explaining halo formation and related phenomena.

Findings

Reproduces the s- and p-state inversion in 10Li.

Explains Coulomb breakup strength observed in 11Li.

Accounts for the charge radius of 11Li.

Abstract

We study the roles of the tensor and pairing correlations on the halo formation in 11Li with an extended 9Li+n+n model. We first solve the ground state of 9Li in the shell model basis by taking 2p-2h states using the Gaussian functions with variational size parameters to take into account the tensor correlation fully. In 11Li, the tensor and pairing correlations in 9Li are Pauli-blocked by additional two neutrons, which work coherently to make the configurations containing the 0p1/2 state pushed up and close to those containing the 1s1/2 state. Hence, the pairing interaction works efficiently to mix the two configurations by equal amount and develop the halo structure in 11Li. For 10Li, the inversion phenomenon of s- and p-states is reproduced in the same framework. Our model furthermore explains the recently observed Coulomb breakup strength and charge radius for 11Li.