Gerald Miller
Might Normal Nuclear Matter Be Quarkyonic?
Abstract:
The possibility that nuclear matter might be quarkyonic is considered. Quarkyonic matter is high baryon density matter that can be approximately thought of as a filled Fermi sea of quarks surrounded by a shell of nucleons. Thus, nucleon occupation probabilities are depleted for low momentum nucleons. Plausibility arguments for the existence of quarkyonic matter, based on experimental measurements of deep inelastic scattering on nucleons, are presented. Then a model of nuclear matter that includes
nucleon interactions with a σ meson and a pion that to provide the necessary attraction. This model is similar the well-known Walecka model, but the necessary repulsive stabilizing forces are provided by the limit that the quark occupation probability must be less than unity. It turns out that isospin-symmetric nuclear matter binds with acceptable values of the compressibility and other parameters for nuclear matter at saturation. Quarkyonic matter predicts a strong depletion of nucleons in normal nuclear matter at low momentum. Such a depletion for nucleon momenta less than 120 MeV is shown to be consistent with quasi-elastic electron scattering data.