QCD vacuum and baryon masses

We propose a novel approach to study a possible role of the quantum chromodynamics vacuum in nuclear and hadron physics. Our proposal is essentially to introduce a candidate of the QCD vacuum through a gluon background field and calculate physical quantities as a function of the background field. In the present work we adopt the Copenhagen (spaghetti) vacuum. As a first application of the our approach, we investigate the effects of the Copenhagen vacuum on the ground-state baryon masses. We find that the baryon mass does depend on a parameter that characterizes the Copenhagen vacuum and satisfies the Gell-Mann-Okubo mass relation for the baryon octet. We also estimate the value of the parameter and discuss the chiral invariant nucleon mass in our framework.