8,679 research outputs found
Results on improved KS dynamical configurations: spectrum, decay constants, etc
The MILC Collaboration has been producing ensembles of lattice configurations
with three dynamical flavors for the past few years. There are now results for
three lattice spacings for a variety of light and strange quark masses, ranging
down to , where is the dynamical strange quark mass and
is the common mass of the and quarks. Recently, the Fermilab,
HPQCD, MILC and UKQCD collaborations have presented a summary of results
obtained using these lattices. Compared with quenched results, these new
calculations show great improvement in agreement with experiment. This talk
addresses the technical improvements that make these calculations possible and
provides additional details of calculations not presented in the initial
summary. We demonstrate that a wide range of hadronic observables can now be
calculated to 2--3% accuracy.Comment: 10 pages, 17 figures (16 in color), Lattice2003(plenary), Plenary
talk presented at Lattice 2003, Tsukuba, Japan, July 15-19. Also presented at
Lattice Hadron Physics workshop, Cairns, Australia, July 22-30, 200
Distributional effects of direct payments in Switzerland
The switch from market-support to direct payments in Switzerland had impacts on the income distribution among farmers. In this paper, the distributional effect of the switch as a whole and of the different kinds of direct payments are elaborated through a presentation of different decomposed Gini coefficients. Although the income distribution in Swiss Agriculture is still more equal than in most other countries, the Gini coefficient has risen from 0.27 in 1990 to 0.38 in 2009 and is by now strongly dependent on the composition of direct payments. Off-farm income and direct payments decrease, while market income increases income inequality.income distribution, direct payments, Gini decomposition, agricultural policy, Agricultural and Food Policy, Q00, Q18, Q28.,
2+1 flavor simulations of QCD with improved staggered quarks
The MILC collaboration has been performing realistic simulations of full QCD
with 2+1 flavors of improved staggered quarks. Our simulations allow for
controlled continuum and chiral extrapolations. I present results for the light
pseudoscalar sector: masses and decay constants, quark masses and
Gasser-Leutwyler low-energy constants. In addition I will present some results
for heavy-light mesons, decay constants and semileptonic form factors, obtained
in collaboration with the HPQCD and Fermilab lattice collaborations. Such
calculations will help in the extraction of CKM matrix elements from
experimental measurements.Comment: To appear in the proceedings of QNP06, IVth International Conference
on Quarks and Nuclear Physics, Madrid, June 200
Heavy-light decay constants using clover valence quarks and three flavors of dynamical improved staggered quarks
Starting in 2001, the MILC Collaboration began a large scale calculation of
heavy-light meson decay constants using clover valence quarks on ensembles of
three flavor configurations. For the coarse configurations, with a=0.12 fm,
eight combinations of dynamical light and strange quarks have been analyzed.
For the fine configurations, with a=0.09 fm, three combinations of quark masses
are studied. Since we last reported on this calculation, statistics have been
increased on the fine ensembles, and, more importantly, a preliminary value for
the perturbative renormalization of the axial-vector current has become
available. Thus, results for f_B, f_{B_s}, f_D and f_{D_s} can, in principle,
be calculated in MeV, in addition to decay-constant ratios that were calculated
previously.Comment: Talk presented at Lattice2004(heavy), Fermilab, June 21-26, 2004; 3
pages, 3 color figure
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