QCD sum rules for nucleons in nuclear matter III

Abstract

The self-energies of quasinucleon states in nuclear matter are investigated using a finite-density QCD sum-rule approach developed previously. The sum rules are obtained for a general QCD interpolating field for the nucleon. The key phenomenological inputs are the nucleon \ensuremath{\sigma} term, the strangeness content of the nucleon, and quark and gluon distribution functions deduced from deep-inelastic scattering. The emphasis is on testing the sensitivity and stability of sum-rule predictions to variations of the condensates and other input parameters. At nuclear matter saturation density, the Lorentz vector self-energy is found to be positive with a magnitude of a few hundred MeV, which is comparable to that suggested by relativistic nuclear phenomenology. This result is quite stable. The prediction for the scalar self-energy is very sensitive to the undertermined values of the in-medium four-quark condensates.