Accurate nucleon-nucleon potential with charge-independence breaking

TLDR

The model builds on the Argonne v14 potential, extending its 14 operator components to a charge‑independent framework. The authors introduce the Argonne v18 potential, a high‑quality nucleon‑nucleon interaction incorporating explicit charge dependence and asymmetry. They augment the charge‑independent core with three charge‑dependent and one charge‑asymmetric operators, add a full electromagnetic interaction, and fit the 40 adjustable parameters directly to the Nijmegen pp and np scattering database, low‑energy nn scattering data, and the deuteron binding energy. The resulting potential achieves a χ² per datum of 1.09 across 4301 pp and np data from 0 to 350 MeV.

Abstract

We present a new high-quality nucleon-nucleon potential with explicit charge dependence and charge asymmetry, which we designate Argonne ${\mathit{v}}_{18}$. The model has a charge-independent part with 14 operator components that is an updated version of the Argonne ${\mathit{v}}_{14}$ potential. Three additional charge-dependent and one charge-asymmetric operators are added, along with a complete electromagnetic interaction. The potential has been fit directly to the Nijmegen pp and np scattering database, low-energy nn scattering parameters, and deuteron binding energy. With 40 adjustable parameters it gives a ${\mathrm{\ensuremath{\chi}}}^{2}$ per datum of 1.09 for 4301 pp and np data in the range 0--350 MeV.