Three-body forces and the limit of oxygen isotopes

TL;DR

This paper explains the anomaly in the oxygen isotope neutron drip-line using three-nucleon forces, shifting the predicted limit from $^{28}$O to the observed $^{24}$O, impacting nuclear physics and astrophysics.

Contribution

First microscopic explanation of the oxygen isotope anomaly based on three-nucleon forces, improving predictions of neutron-rich nuclei limits.

Findings

Reveals repulsive effects of three-nucleon forces on excess neutrons.

Shifts the predicted neutron drip-line from $^{28}$O to $^{24}$O.

Impacts understanding of heavy element synthesis in neutron-rich environments.

Abstract

The limit of neutron-rich nuclei, the neutron drip-line, evolves regularly from light to medium-mass nuclei except for a striking anomaly in the oxygen isotopes. This anomaly is not reproduced in shell-model calculations derived from microscopic two-nucleon forces. Here, we present the first microscopic explanation of the oxygen anomaly based on three-nucleon forces that have been established in few-body systems. This leads to repulsive contributions to the interactions among excess neutrons that change the location of the neutron drip-line from $^{28}$O to the experimentally observed $^{24}$O. Since the mechanism is robust and general, our findings impact the prediction of the most neutron-rich nuclei and the synthesis of heavy elements in neutron-rich environments.