8,679 research outputs found

    Results on improved KS dynamical configurations: spectrum, decay constants, etc

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    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 ml=0.1msm_l=0.1 m_s, where msm_s is the dynamical strange quark mass and mlm_l is the common mass of the uu and dd 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

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    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

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    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

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    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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