941 research outputs found
Dynamics of Langevin Simulation
This chapter [of a supplement to Prog. Theo. Phys.] reviews numerical
simulations of quantum field theories based on stochastic quantization and the
Langevin equation. The topics discussed include renormalization of finite
step-size algorithms, Fourier acceleration, and the relation of the Langevin
equation to hybrid stochastic algorithms and hybrid Monte Carlo.Comment: 20 p
Numerical Tests of the Improved Fermilab Action
Recently, the Fermilab heavy-quark action was extended to include
dimension-six and -seven operators in order to reduce the discretization
errors. In this talk, we present results of the first numerical simulations
with this action (the OK action), where we study the masses of the quarkonium
and heavy-light systems. We calculate combinations of masses designed to test
improvement and compare results obtained with the OK action to their
counterparts obtained with the clover action. Our preliminary results show a
clear improvement.Comment: 7 pages, 3 figures, Talk presented at 28th International Symposium On
Lattice Field Theory (Lattice 2010) 13-19 Jun 2010, Villasimius, Sardinia,
Ital
Non-perturbative Renormalization of Lattice Operators
We briefly review and compare three methods (one perturbative, one based on
Ward Identities and one non-perturbative) for the calculation of the
renormalization constants of lattice operators. The following results are
presented: (a) non perturbative renormalization of the operators with light
quarks; (b) the renormalization constants with a heavy (charm) quark mass and
its KLM improvement; (c) the non perturbative determination of the mixing of
the operator.Comment: 9 pages, uuencoded PS file, 8 figures included, 1 tabl
Dual Superconductor Mechanism of Confinement on the Lattice
We investigate the dual superconductor mechanism of confinement for pure
SU(2) lattice gauge theory in the maximally abelian gauge. We focus on the the
dual Meissner effect. We find that the transverse distribution of the
longitudinal chromoelectric field due to a static quark-antiquark pair
satisfies the dual London equation. Moreover we show that the size of the flux
tube scales according to asymptotic freedom.Comment: LaTeX, 9 pages, 6 figures available as a PostScript file from L.
Cosmai, BARI - TH 110/9
Accumulating evidence for nonstandard leptonic decays of D_s mesons
The measured rate for D_s -> l nu decays, where l is a muon or tau, is larger
than the standard model prediction, which relies on lattice QCD, at the 3.8
sigma level. We discuss how robust the theoretical prediction is, and we show
that the discrepancy with experiment may be explained by a charged Higgs boson
or a leptoquark.Comment: 4 pages; v2 conforms with PRL versio
Monopole Spectra in non-Abelian Gauge Theories
We study the continuum limit of the length spectrum of magnetic monopole
structures found after various Abelian projections of pure gauge SU(2),
including the maximally Abelian gauge. We comment on Gribov copies, and
measurements of the string tension.Comment: Talk presented at LATTICE96(topology) LaTeX, with 4 LaTeX figure
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