Alpha-particle condensation in 16O via a full four-body OCM calculation

TL;DR

This paper uses a comprehensive four-body calculation to identify a dilute, alpha-particle condensate state in 16O, providing evidence for alpha clustering and condensate features in nuclear structure.

Contribution

It introduces a full four-body OCM calculation in a large basis to accurately reproduce and analyze the 4 alpha condensate state in 16O.

Findings

Identifies the 0_6^+ state as a 4 alpha condensate with 61% condensate fraction.

Reproduces the spectrum up to the 0_6^+ state consistent with experimental data.

Finds the 0_6^+ state at about 2 MeV above the 4 alpha threshold with dilute density.

Abstract

In order to explore the 4 \alpha-particle condensate state in 16O, we solve a full four-body equation of motion based on the 4 \alpha OCM (Orthogonality Condition Model) in a large 4 \alpha model space spanned by Gaussian basis functions. A full spectrum up to the 0_6^+ state is reproduced consistently with the lowest six 0^+ states of the experimental spectrum. The 0^+_6 state is obtained at about 2 MeV above the 4 \alpha breakup threshold and has a dilute density structure, with a radius of about 5 fm. The state has an appreciably large \alpha condensate fraction of 61 %, and a large component of \alpha+12C(0_2^+) configuration, both features being reliable evidence for this state to be of 4 \alpha condensate nature.