Effective Mass Generation of Off-diagonal Gluons and Abelian Dominance in the Maximally Abelian Gauge in QCD

We study the properties of gluons in QCD in the maximally abelian (MA) gauge. In the MA gauge, the off-diagonal gluon behaves as the massive vector boson with the mass $\Meff \simeq 1.2 {\rm GeV}$, and therefore the off-diagonal gluon cannot carry the long-range interaction for $r \gg \Meff^{-1} \simeq 0.2$ fm. The essence of the infrared abelian dominance in the MA gauge is physically explained with the generation of the off-diagonal gluon mass $\Meff \simeq 1.2 {\rm GeV}$ induced by the MA gauge fixing, and the off-diagonal gluon mass generation would predict general infrared abelian dominance in QCD in the MA gauge. We report also the off-diagonal gluon propagator at finite temperature.