Infrared behavior of the gluon propagator on a large volume lattice - art.no. 051501

The first calculation of the gluon propagator using an O(a(2)) improved act ion with the corresponding O(a(2)) improved Landau gauge fixing condition i s presented. The gluon propagator obtained from the improved action and imp roved Landau gauge condition is compared with earlier unimproved results on similar physical lattice volumes of 3.2(3) X 6.4 fm(4). We find agreement between the improved propagator calculated on a coarse lattice with lattice spacing a = 0.35 fm and the unimproved propagator calculated on a fine lat tice with spacing a = 0.10 fro. This motivates us to calculate the gluon pr opagator on a coarse large-volume lattice 5.6(3) X 11.2 fm(4). The infrared behavior of previous studies is confirmed in this work. The gluon propagat or is enhanced at intermediate momenta acid suppressed at infrared momenta. Therefore the observed infrared suppression of the Landau gauge gluon prop agator is not a finite volume effect.