Nuclear Fermi gas model ($p_{F,i}=\hslash (3{\pi }^2{n}_i{)}^{1/3}$)

A model with separate filled proton and neutron momentum seas in a nuclear mean field. Each spin-half species has two spin states, so counting momentum-space cells gives $p_{F,i}=\hslash (3{\pi }^2{n}_i{)}^{1/3}$. It describes typical nucleon motion and a kinetic contribution to nuclear symmetry energy, but binding requires additional interactions.

The motion of particles occupying the momentum sea of a Fermi gas, especially nucleons in an atomic nucleus. It persists at zero temperature and broadens scattering kinematics relative to a stationary-nucleon approximation.