3,204 research outputs found
Quark and Gluon Propagators in Covariant Gauges
We present data for the gluon and quark propagators computed in the standard
lattice Landau's gauge and for three values of the covariant gauge-fixing
parameter lambda=0,8,16. Our results are obtained using the SU(3) Wilson action
in the quenched approximation at beta=6.0 and volume=16^3x32.Comment: Lattice2001(theorydevelop
Numerical Exploration of the RI/MOM Scheme Gauge Dependence
The gauge dependence of some fermion bilinear RI/MOM renormalization
constants is studied by comparing data which have been gauge-fixed in two
different realizations of the Landau gauge and in a generic covariant gauge.
The very good agreement between the various sets of results and the theory
indicates that the numerical uncertainty induced by the lattice gauge-fixing
procedure is below the statistical errors of our data sample which is of the
order of (1-1.5)%.Comment: 3 pages, 2 figures, Lattice2002(theoretical
Remarks on the Gauge Dependence of the RI/MOM Renormalization Procedure
The RI/MOM non-perturbative renormalization scheme is studied on the lattice
in SU(3) quenched QCD with Wilson fermions. The gauge dependence of some
fermion bilinear renormalization constants is discussed by comparing data which
have been gauge-fixed in two different realizations of the Landau gauge and in
a generic covariant gauge. The very good agreement between the various sets of
results and the theory indicates that the numerical uncertainty induced by the
lattice gauge-fixing procedure is moderate and below the statistical errors.Comment: 11 pages, 3 figure
Light hadron spectra and wave functions in quenched QCD with overlap quarks on a large lattice
A simulation of quenched QCD with the overlap Dirac operator has been
completed using 100 Wilson gauge configurations at beta=6 on an 18^3x64
lattice. We present results for meson and baryon masses, meson final state
"wave functions'' and other observables.Comment: 5 LaTeX pages (espcrc2.sty), 13 figures. Combined contributions by
J.H., L.L. and C.R. at Lattice2004(spectrum), Fermilab, June 21-26, 200
Preliminary results from a simulation of quenched QCD with overlap fermions on a large lattice
We simulate quenched QCD with the overlap Dirac operator. We work with the
Wilson gauge action at beta=6 on an 18^3x64 lattice. We calculate quark
propagators for a single source point and quark mass ranging from am_q=0.03 to
0.75. We present here preliminary results based on the propagators for 60 gauge
field configurations.Comment: Lattice2003(chiral); 9 latex pages (espcrc2.sty), 13 figures. Based
on talks given by C.H., L.L. and C.R. at 21st International Symposium on
Lattice Field Theory (Lattice 2003), Tsubuka, Japan, 15-19 July 2003.
Repitition in references corrected and one reference adde
B_K from quenched overlap QCD
We present an exploratory calculation of the standard model Delta S=2 matrix
element relevant for indirect CP violation in K -> pi pi decays. The
computation is performed with overlap fermions in the quenched approximation at
beta=6.0 on a 16^3x32 lattice. The resulting bare matrix element is
renormalized non-perturbatively. Our preliminary result is B_K^{NDR}(2
GeV)=0.61(7), where the error does not yet include an estimate of systematic
uncertainties.Comment: 3 pages, 2 figures, Lattice2002(matrixel). Parallel session talk by
L. Lellouch at the 20th International Symposium on Lattice Field Theory
(Lattice 2002), Boston, Massachusetts, 24-29 June 200
Leading isospin-breaking corrections to pion, kaon and charmed-meson masses with Twisted-Mass fermions
We present a lattice computation of the isospin-breaking corrections to
pseudoscalar meson masses using the gauge configurations produced by the
European Twisted Mass collaboration with dynamical quarks at
three values of the lattice spacing ( and fm)
with pion masses in the range MeV. The strange and
charm quark masses are tuned at their physical values. We adopt the RM123
method based on the combined expansion of the path integral in powers of the
- and -quark mass difference () and of the
electromagnetic coupling . Within the quenched QED approximation,
which neglects the effects of the sea-quark charges, and after the
extrapolations to the physical pion mass and to the continuum and infinite
volume limits, we provide results for the pion, kaon and (for the first time)
charmed-meson mass splittings, for the prescription-dependent parameters
, \epsilon_\gamma(\overline{MS}, 2~\mbox{GeV}),
\epsilon_{K^0}(\overline{MS}, 2~\mbox{GeV}), related to the violations of the
Dashen's theorem, and for the light quark mass difference (\widehat{m}_d -
\widehat{m}_u)(\overline{MS}, 2~\mbox{GeV}).Comment: 47 pages, 20 figures, 4 tables; comments on QED and QCD splitting
prescriptions added; version to appear in PR
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