Energies and radii of light nuclei around unitarity

TL;DR

This paper uses effective field theory to analyze light nuclei near the unitarity limit, demonstrating a perturbative approach that accurately predicts their energies and radii.

Contribution

It introduces a perturbative expansion around the unitarity limit for nuclear forces, improving predictions of light nuclei properties.

Findings

Good convergence of the expansion for binding energies of A=3,4 nuclei

Accurate predictions of nuclear radii

Framework applicable to universal physics regimes

Abstract

Light nuclei fall within a regime of universal physics governed by the fact that the two-nucleon scattering lengths are large compared to the typical nuclear interaction range set by one-pion exchange. This places nuclear physics near the so-called unitarity limit in which the scattering lengths are exactly infinite. Effective field theory provides a powerful theoretical framework to capture this separation of scales in a systematic way. It is shown here that the nuclear force can be constructed as a perturbative expansion around the unitarity limit and that this expansion has good convergence properties for both the binding energies of $A=3,4$ nuclei as well as for the radii of these states.