The role of the in-medium four-quark condensates revised

TL;DR

This paper revises the calculation of nucleon self-energies in nuclear matter using QCD sum rules, emphasizing the importance of relativistic models and beyond-gas approximation effects on four-quark condensates.

Contribution

It introduces a refined calculation of four-quark condensates in QCD sum rules, including relativistic effects and higher-order terms, improving the understanding of nucleon properties in nuclear matter.

Findings

Results align with traditional nuclear physics methods

Relativistic models significantly affect condensate calculations

Inclusion of multi-body forces enhances accuracy

Abstract

We calculate the nucleon self-energies in nuclear matter in the QCD sum rules approach, taking into account the contributions of the four-quark condensates. We analyze the dependence of the results on the model employed for the calculation of the condensates and demonstrate that the relativistic character of the models is important. The condensates are calculated with inclusion of the most important terms beyond the gas approximation. This corresponds to inclusion of the two-body nucleon forces and of the most important three-body forces. The results are consistent with the convergence of the operator product expansion. The density dependence of the nucleon self-energies is obtained. The results are consistent with those obtained by the standard nuclear physics methods, thus inspiring further development of the approach.