130 research outputs found
Light Quark Physics with Dynamical Wilson Fermions
We present results for spectroscopy, quark masses and decay constants
obtained from SESAM's and TkL's large statistics simulations of QCD with two
dynamical Wilson fermions.Comment: 3 pages; to appear in the proceedings of Lat.'9
Glueballs and string breaking from full QCD
We present results on the static potential, and torelon and glueball masses
from simulations of QCD with two flavours of dynamical Wilson fermions on
and lattices at .Comment: Talk presented by Gunnar Bali at International Symposium on Lattice
Field Theories (Lattice 97), Edinburgh, July 1997, 3 pages LaTeX
(epscrc2.sty) with 4 eps figure
apeNEXT: A multi-TFlops Computer for Simulations in Lattice Gauge Theory
We present the APE (Array Processor Experiment) project for the development
of dedicated parallel computers for numerical simulations in lattice gauge
theories. While APEmille is a production machine in today's physics simulations
at various sites in Europe, a new machine, apeNEXT, is currently being
developed to provide multi-Tflops computing performance. Like previous APE
machines, the new supercomputer is largely custom designed and specifically
optimized for simulations of Lattice QCD.Comment: Poster at the XXIII Physics in Collisions Conference (PIC03),
Zeuthen, Germany, June 2003, 3 pages, Latex. PSN FRAP15. Replaced for adding
forgotten autho
Critical Dynamics of the Hybrid Monte Carlo Algorithm
We investigate the critical dynamics of the Hybrid Monte Carlo algorithm
approaching the chiral limit of standard Wilson fermions. Our observations are
based on time series of lengths O(5000) for a variety of observables. The
lattice sizes are 16^3 x 32 and 24^3 x 40. We work at beta=5.6, and
kappa=0.156, 0.157, 0.1575, 0.158, with 0.83 > m_pi/m_rho > 0.55. We find
surprisingly small integrated autocorrelation times for local and extended
observables. The dynamical critical exponent of the exponential
autocorrelation time is compatible with 2. We estimate the total computational
effort to scale between V^2 and V^2.25 towards the chiral limit.Comment: 3 pages, Latex with espcrc2.sty and postscript figures, Talk given at
Lattice 9
SESAM and TXL Results for Wilson Action--A Status Report
Results from two studies of full QCD with two flavours of dynamical Wilson
fermions are presented. At beta=5.6, the region 0.83 > m_pi/m_rho > 0.56 at
m_pia > 0.23 L^{-1} is explored. The SESAM collaboration has generated
ensembles of about 200 statistically independent configurations on a 16^3 x
32-lattice at three different kappa-values and is entering the final phase of
data analysis. The TXL simulation on a 24^3 x 40-lattice at two kappa-values
has reached half statistics and data analysis has started recently, hence most
results presented here are preliminary. The focus of this report is fourfold:
we demonstrate that algorithmic improvements like fast Krylov solvers and
parallel preconditioning recently introduced can be put into practise in full
QCD simulations, we present encouraging observations as to the critical
dynamics of the Hybrid Monte Carlo algorithm in the approach to the chiral
limit, we mention signal improvements of noisy estimator techniques for
disconnected diagrams to the pi-N sigma term, and we report on SESAM's results
for light hadron spectrum, light quark masses, and heavy quarkonia.Comment: 24 pages, tex + postscript figures, to appear in Proceedings of Int.
Workshop "Lattice QCD on Parallel Computers", University of Tsukuba, Japa
Modern Electronic Techniques Applied to Physics and Engineering
Contains reports on two research projects
Non-perturbatively Improved Heavy-Light Mesons: Masses and Decay Constants
We present a study of the heavy-light spectrum and of the D- and B-meson
decay constants. The results wer e obtained in the quenched approximation, by
using the non-perturbatively improved Clover lattice action at beta=6.2, with a
sample of 100 configurations, on a 24^3 x 64 lattice. After a careful analysis
of th e systematic errors present in the extraction of the physical results, by
assuming quite conservative discretization errors, we find f_Ds=231 +/-
12^{+6}_{-1} MeV, f_D = 211 +/- 14^{+0}_{-12} MeV, f_Ds/f_D=1.10(2), f_Bs = 204
+/- 16^{+28}_{-0} MeV, f_B = 179 +/- 18^{+26}_{-9} MeV,
f_Bs/f_B=1.14(3)^{+0}_{-1}. Our results, which have smaller discretization
errors than many previous estimates at fixed value of the lattice spacing ,
support a large value of f_B in the quenched approximation.Comment: 26 pages, 9 Postscript figure
The apeNEXT project (Status report)
We present the current status of the apeNEXT project. Aim of this project is
the development of the next generation of APE machines which will provide
multi-teraflop computing power. Like previous machines, apeNEXT is based on a
custom designed processor, which is specifically optimized for simulating QCD.
We discuss the machine design, report on benchmarks, and give an overview on
the status of the software development.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 8 pages, LaTeX, 12 eps figures. PSN
THIT00
Modern Electronic Techniques Applied to Physics and Engineering
Contains reports on three research projects
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