33,475 research outputs found
Recent results using all-point quark propagators
Pseudofermion methods for extracting all-point quark propagators are
reviewed, with special emphasis on techniques for reducing or eliminating
autocorrelations induced by low eigenmodes of the quark Dirac operator. Recent
applications, including high statistics evaluations of hadronic current
correlators and the pion form factor, are also described.Comment: LateX, 3 pages, 6 eps figures, Lattice2002(algor), corrected some
typo
Unquenched Studies Using the Truncated Determinant Algorithm
A truncated determinant algorithm is used to study the physical effects of
the quark eigenmodes associated with eigenvalues below 420 MeV. This initial
high statistics study focuses on coarse () lattices (with O()
improved gauge action), light internal quark masses and large physical volumes.
Three features of full QCD are examined: topological charge distributions,
string breaking as observed in the static energy and the eta prime mass.Comment: Lattice2001(confinement); 3pgs(Latex), 4figs.(ps
Physical Effects of Infrared Quark Eigenmodes in LQCD
A truncated determinant algorithm is used to study the physical effects of
the quark eigenmodes associated with eigenvalues below 400 MeV. This initial
study focuses on coarse lattices (with O(a^2) improved gauge action), light
internal quark masses and large physical volumes. Four bellwether full QCD
processes are discussed: topological charge distributions, the eta prime
propagator, string breaking as observed in the static energy and the rho decay
into two pions.Comment: LATTICE99(Confinement); 3pgs(Latex), 4figs.(eps
Hadronic Correlators from All-point Quark Propagators
A method for computing all-point quark propagators is applied to a variety of
processes of physical interest in lattice QCD. The method allows, for example,
efficient calculation of disconnected parts and full momentum-space 2 and 3
point functions. Examples discussed include: extraction of chiral Lagrangian
parameters from current correlators, the pion form factor, and the unquenched
eta-prime.Comment: LATTICE01(Algorithms and Machines
Key Components and Best Practices for Environmental Impact Assessments
New and emerging activities pose risks to the conservation and sustainable development of ABNJ in the absence of prior assessment, and remain a significant gap under UNCLOS. Environmental impact assessments and strategic environmental assessments are widely accepted as valuable tools for incorporating environmental and social concerns into decision making processes with respect to specific projects or activities (EIAs) or policies, plans or programmes (SEAs). The development of a new international instrument to address the conservation and sustainable use of marine biological diversity in areas beyond national jurisdiction ("international Instrument") is an opportunity to incorporate best practices for EIAs and SEAs already found under a number of multilateral and regional agreements, and apply lessons learned from their application. Importantly, the new Instrument should also provide the mechanism for the assessment of cumulative impacts of activities and climate change
City strategy : final evaluation
The City Strategy (CS) concept was first announced in the 2006 Welfare Reform Green Paper – A new deal for welfare: Empowering people to work. CS was designed at a time of growth in the national economy to combat enduring pockets of entrenched worklessness and poverty in urban areas by empowering local institutions to come together in partnerships to develop locally sensitive solutions. It was premised on the idea that developing a better understanding of the local welfare to work arena would allow partnerships to align and pool funding and resources to reduce duplication of services and fill gaps in provision. The ‘theory of change’ underlying CS suggested that such an approach would result in more coordinated services which would be able to generate extra positive outcomes in terms of getting people into jobs and sustaining them in employment over and above existing provision.
CS was initially set to run for two years from April 2007 to March 2009 in 15 CS Pathfinder (CSP) areas, varying in size from five wards in one town through single local authority areas to subregional groupings of multiple local authority areas, across Great Britain. In July 2008, the Secretary of State for Work and Pensions announced an extension for a further two years to March 2011. In April 2009, two local areas in Wales, which were in receipt of monies from the Deprived Areas Fund (DAF), were invited by the Department for Work and Pensions (DWP) to form local partnerships with a similar remit to the CSPs, albeit more limited in scope – to develop locally sensitive solutions to economic inactivity, to the CSPs.
During the period that the CS initiative was operational, economic conditions changed markedly with a severe recession, followed by fragile recovery. The CSPs had to cope with ongoing changes in policy throughout the lifetime of the CS initiative, including a General Election and a new Coalition Government at Westminster early in the fourth year. While policy changes are a fact of life for local practitioners operating in the welfare to work arena, the global recession in 2008/09 marked a fundamental change in the context in which local partnerships operated
Heavy-Light Wavefunctions in Lattice QCD
Using a multistate smearing method, Coulomb gauge wave functions of
heavy-light mesons are studied in lattice QCD. Wave functions for the ground
state, the first radially excited S-wave state, and the lowest P-wave states of
a heavy-light meson are calculated in quenched approximation. The results are
found to be in remarkably good agreement with the predictions of a simple
relativistic quark model.Comment: Latex file inputs psfig.tex, and espcrc2.sty, 3 figures in uuencoded
fil
Electromagnetic Structure of Light Baryons in Lattice QCD
A method in which electromagnetic properties of hadrons are studied by direct
simulation of dynamical photon effects is applied to the extraction of the
isomultiplet structure of the octet baryons. Using 187 configurations at
with Wilson action, and up and down quark masses determined from
the meson spectrum, the nucleon splitting is found to be MeV; the hyperon splittings are found to be
, ,
MeV. Estimated systematic corrections arising
from finite volume and the quenched approximation are included in these
results.Comment: Talk presented at LATTICE96(phenomenology
String Breaking in Four Dimensional Lattice QCD
Virtual quark pair screening leads to breaking of the string between
fundamental representation quarks in QCD. For unquenched four dimensional
lattice QCD, this (so far elusive) phenomenon is studied using the recently
developed truncated determinant algorithm (TDA). The dynamical configurations
were generated on an Athlon 650 MHz PC. Quark eigenmodes up to 420 MeV are
included exactly in these TDA studies performed at low quark mass on large
coarse (but O() improved) lattices. A study of Wilson line correlators in
Coulomb gauge extracted from an ensemble of 1000 two-flavor dynamical
configurations reveals evidence for flattening of the string tension at
distances R approximately 1 fm.Comment: 16 pages, 5 figures, Latex (deleted extraneous eps figure file
- …