The color gauge invariance and a possible origin of a mass gap in QCD

Understand

The general scale parameter, having the dimensions of mass squared, is dynamically generated in the QCD gluon sector.

• It is introduced through the difference between the regularized full gluon self-energy and its value at some finite point.
• It violates transversality of the full gluon self-energy.
• The Slavnov-Taylor identity for the full gluon propagator, when it is given by the corresponding equation of motion, is also violated by it.