nucleonbased

Nucleonbased is a term used in physics to describe a class of theoretical and computational approaches that describe atomic nuclei and nucleonic systems predominantly in terms of nucleons (protons and neutrons) and their interactions, rather than attempting to resolve subnucleonic degrees of freedom such as quarks and gluons. In this view, the nucleus is treated as a many-body system of nucleons governed by effective interactions that encode the underlying strong force at low energies.

Applications and models in the nucleonbased framework include the nuclear shell model, mean-field and energy density functional theories, and various reaction theories using nucleon-nucleus optical potentials. Ab initio methods sometimes still operate in a nucleonbased framework, using realistic nucleon-nucleon and three-nucleon forces fitted to scattering data and light nuclei. At higher energies or shorter distances, quark-gluon dynamics becomes more directly relevant, and nucleonbased descriptions may be approximations or effective theories.

Limitations of nucleonbased approaches include reliance on phenomenological potentials or truncated model spaces, with accuracy depending on the fidelity of the effective interactions. They may neglect internal nucleon structure and meson-exchange currents and can have limited predictive power in extreme environments such as very high density or high energy.

Historically, the term is not a strict technical category but a descriptive label used across nuclear physics to distinguish degrees of freedom. It contrasts with quark-based or parton-level descriptions and fits within the broader framework of effective field theories that integrate out high-energy degrees of freedom. See also: nucleon-nucleon interaction, shell model, mean-field theory, quantum chromodynamics, effective field theory.