Color-Magnetic Permeability of QCD Vacuum

In a preYious papern we have shown that the true ground-state yacuum of QCD (quantum chromodynamics) has lower energy than the "perturbative vacuum." The MIT bag constant may be given by the energy density difference between the perturbative vacuum and the true ground-state vacuum of QCD, because in the MIT bag model the perturbative vacuum is used inside the bag, while on the outside we have for the fields an impenetrable vacuum. In the present paper we calculate the color-magnetic permeability lie of the QCD true vacuum and show this value to be 1/2 within the quark-one-loop approximation. A gl uon-loop contribution to the QCD vacuum is shown to be neglected when the number of quark flavor is large. If lie= 0, the vacuum is the perfect diamagnet so that quarks and gluons may be confined inside Abrikosov flux lines by the Meissner effect. However, m view of our result fie= 1/2 this confinement is still imperfect at this stage. We begin with a review of our previous work. We adopt the following expression of the SU (2) background gauge field: