Maria B. Parappilly

Unquenched quark propagator in Landau gauge

[...] We present an unquenched calculation of the quark propagator in Landau gauge with 2� 1 flavors of dynamical quarks. We use configurations generated with an improved staggered (‘‘Asqtad’’) action by the MILC Collaboration. This quark action has been seen to have excellent rotational symmetry and scaling properties in the quenched quark propagator. Quenched and dynamical calculations are performed on a 20 3 � 64 lattice with a nominal lattice spacing of a � 0:125 fm. The matched quenched and dynamical lattices allow us to investigate the relatively subtle sea-quark effects, and even in the quenched case the physical volume of these lattices gives access to lower momenta than our previous study. We calculate the quark mass function and renormalization function for a variety of valence and sea-quark masses.

Unquenched gluon propagator in Landau gauge

[...] Using lattice quantum chromodynamics ~QCD! we perform an unquenched calculation of the gluon propagator in Landau gauge. We use configurations generated with the AsqTad quark action by the MILC collaboration for the dynamical quarks and compare the gluon propagator of quenched QCD ~i.e., the pure Yang-Mills gluon propagator! with that of 211 flavor QCD. The effects of the dynamical quarks are clearly visible and lead to a significant reduction of the nonperturbative infrared enhancement relative to the quenched case.

Scaling behavior and positivity violation of the gluon propagator in full QCD

The Landau-gauge gluon propagator is studied using the coarse and fine dynamical MILC configurations. The effects of dynamical quarks are clearly visible and lead to a reduction of the nonperturbative infrared enhancement relative to the quenched case. Lattice spacing effects are studied and found to be small. The gluon spectral function is shown to clearly violate positivity in both quenched and full QCD.

Scaling behavior of the quark propagator in full QCD

American Physical Society, One Research Road, Box 9000, Ridge, NY 11961-9000, USA(Dated: February 1, 2008)We study the scaling behavior of the quark propagator on two lattices with similar physical volumein Landau gauge with 2+1 flavors of dynamical quarks in order to test whether we are close to thecontinuum limit for these lattices. We use configurations generated with an improved staggered(“Asqtad”) action by the MILC collaboration. The calculations are performed on 28

Effects of dynamical sea-quarks on quark and gluon propagators

We present an unquenched calculation of the quark propagator in Landau gauge with 2+1 flavors of dynamical quarks. We study the scaling behavior of the quark propagator in full QCD on two lattices with different lattice spacings and similar physical volume. We use configurations generated with an improved staggered (“Asqtad”) action by the MILC collaboration.