Energies and radii of light nuclei around unitarity

Understand

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.