Gluon propagators in maximally Abelian gauge in SU(3) lattice QCD

In SU(3) lattice QCD, we study diagonal and off-diagonal gluon propagators in the maximally Abelian gauge with U(1)(3) x U(1)(8) Landau gauge fixing. These propagators are studied both in the coordinate space and in the momentum space. The Monte Carlo simulation is performed on 16(4) at beta = 6.0 and 32(4) at beta = 5.8 and 6.0 at the quenched level. In the four-dimensional Euclidean space-time, the effective mass of diagonal gluons is estimated as M-diag similar or equal to 0.3 GeV and that of off-diagonal gluons as M-off similar or equal to 1 GeVin the region of r = 0.4-1.0 fm. In the momentum space, the effective mass of diagonal gluons is estimated as M-diag similar or equal to 0.3 GeV and that of off-diagonal gluons as M-off similar or equal to 1 GeV in the region of p < 1.1 GeV. The off-diagonal gluon propagator is relatively suppressed in the infrared region and seems to be finite at zero momentum, while the diagonal gluon propagator is enhanced. Furthermore, we also study the functional form of these propagators in momentum space. These propagators are well fitted by Z/(p(2) + m(2))(nu) with fit parameters, Z, m, and nu in the region of p < 3.0 GeV. From the fit results and lattice calculations, all of the spectral functions of diagonal and off-diagonal gluons would have negative regions. DOI: 10.1103/PhysRevD.87.074506