A New Approach to Physics of Nuclei

TL;DR

This paper employs QCD sum rules to describe nucleons in nuclear matter, linking nucleon properties to QCD condensates and providing insights into nuclear forces and saturation mechanisms.

Contribution

It introduces a QCD-based formalism for nuclear physics, connecting nucleon characteristics to in-medium QCD condensates without phenomenological parameters.

Findings

Consistent values for nucleon effective mass and self-energy at saturation density.

Relation of scalar interaction to pion--nucleon sigma-term.

Reasonable results for axial coupling constant renormalization.

Abstract

We employ the QCD sum rules method for description of nucleons in nuclear matter. We show that this approach provides a consistent formalism for solving various problems of nuclear physics. Such nucleon characteristics as the Dirac effective mass $m^*$ and the vector self-energy $\Sigma_V$ are expressed in terms of the in-medium values of QCD condensates. The values of these parameters at saturation density and the dependence on the baryon density and on the neutron-to-proton density ratio is in agreement with the results, obtained by conventional nuclear physics method. The contributions to $m^*$ and $\Sigma_V$ are related to observables and do not require phenomenological parameters. The scalar interaction is shown to be determined by the pion--nucleon $\sigma$-term. The nonlinear behavior of the scalar condensate may appear to provide a possible mechanism of the saturation. The approach provided reasonable results for renormalization of the axial coupling constant, for the contribution of the strong interactions to the neutron--proton mass difference and for the behavior of the structure functions of the in-medium nucleon. The approach enables to solve the problems which are difficult or unaccessible for conventional nuclear physics methods. The method provides guide-lines for building the nuclear forces. The three-body interactions emerge within the method in a natural way. There rigorous calculation will be possible in framework of self-consistent calculation in nuclear matter of the scalar condensate and of the nucleon effective mass $m^*$.