Fermi Liquid and “QCD” Aspects of the Nucleus

Abstract

Recent exclusive electron scattering results which involve the ejection of a proton from the nucleus, have established properties of the nucleus that can be brought into one-to-one correspondence with Fermi Liquid properties of infinite homogeneous systems. Theoretical calculations in finite nuclei are discussed which establish these “Fermi Liquid” properties by including the coupling of single-particle motion to more complicated states in an energy domain of about 100 MeV around the Fermi energy. Although sufficient to explain the shape of the experimental strength distributions, these calculations need to be supplemented by including the coupling to even higher energy states for quantitative agreement. Such calculations are reported for nuclear matter. These results clearly establish the importance of the coupling between low-lying single-particle states and very high-lying 2p1h-states. This coupling is provided within the constraints of non-relativistic many-particle theory by the use of a strongly repulsive realistic interaction between nucleons. This feature is illustrated with numerical results. The simulation of QCD degrees of freedom in terms of short-range correlations turns out to be crucial for a quantitative understanding of (e, e’p) results as well as other electron scattering data, as will be discussed for various examples.