2,781 research outputs found

    Calculating “Income” for Domestic Support Obligations in the Wake of the COVID-19 Pandemic

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    The ratio FK/Fpi in QCD

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    We determine the ratio FK/Fpi in QCD with Nf=2+1 flavors of sea quarks, based on a series of lattice calculations with three different lattice spacings, large volumes and a simulated pion mass reaching down to about 190 MeV. We obtain FK/Fpi=1.192 +/- 0.007(stat) +/- 0.006(syst). This result is then used to give an updated value of the CKM matrix element |Vus|. The unitarity relation for the first row of this matrix is found to be well observed.Comment: 15 pages, 4 figures, 2 table

    Chiral behavior of pseudo-Goldstone boson masses and decay constants in 2+1 flavor QCD

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    We present preliminary results for the chiral behavior of charged pseudo-Goldstone-boson masses and decay constants. These are obtained in simulations with N_f=2+1 flavors of tree-level, O(a)-improved Wilson sea quarks. In these simulations, mesons are composed of either valence quarks discretized in the same way as the sea quarks (unitary simulations) or of overlap valence quarks (mixed-action simulations). We find that the chiral behavior of the pseudoscalar meson masses in the mixed-action calculations cannot be explained with continuum, partially-quenched chiral perturbation theory. We show that the inclusion of O(a^2) unitarity violations in the chiral expansion resolves this discrepancy and that the size of the unitarity violations required are consistent with those which we observe in the zero-momentum, scalar-isotriplet-meson propagator.Comment: 7 pages, 3 figures, talk by L. Lellouch at the XXV International Symposium on Lattice Field Theory (LATTICE 2007), 30 July - 4 August 2007, Regensburg, German

    How do you spell bird? Effective parent programs to enhance 4-6 year old children's literacy development

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    This research examined the effectiveness of parent programs designed for families to support the literacy learning of their 4-6 year old children. The project began with a literature review analysing six established, effective parent programs that have been reported in the international and national research literature. An analysis of what made each of the programs effective entailed an analysis of the program's target population, the project inputs and activities and the initial, immediate and long term outcomes. To explore further what local parents and families view as effective parent programs for 4-6 year old children the research explored individual site-specific parent programs in operation in South Australian childcare centres, preschools and schools in a range of diverse socioeconomic and geographic sites. Parents and teachers engaged in focus groups to describe ways the schools and centres sustain links between home and school learning. To assess the elements of two existing parent programs to support children's early literacy development, parents and teachers participated in several focus groups. The two programs were the parent component of The Abecedarian Program (2001, 1979) developed in the United States and the South Australian Early Childhood Literacy Includes Parents Staff and Education ECLIPSE program (1997) developed by the South Australian Department of Education and Children's Services (DECS)

    Precision computation of the kaon bag parameter

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    Indirect CP violation in K \rightarrow {\pi}{\pi} decays plays a central role in constraining the flavor structure of the Standard Model (SM) and in the search for new physics. For many years the leading uncertainty in the SM prediction of this phenomenon was the one associated with the nonperturbative strong interaction dynamics in this process. Here we present a fully controlled lattice QCD calculation of these effects, which are described by the neutral kaon mixing parameter B_K . We use a two step HEX smeared clover-improved Wilson action, with four lattice spacings from a\approx0.054 fm to a\approx0.093 fm and pion masses at and even below the physical value. Nonperturbative renormalization is performed in the RI-MOM scheme, where we find that operator mixing induced by chiral symmetry breaking is very small. Using fully nonperturbative continuum running, we obtain our main result B_K^{RI}(3.5GeV)=0.531(6)_{stat}(2)_{sys}. A perturbative 2-loop conversion yields B_K^{MSbar-NDR}(2GeV)=0.564(6)_{stat}(3)_{sys}(6)_{PT}, which is in good agreement with current results from fits to experimental data.Comment: 10 pages, 7 figures. v2: Added one reference and one figure, replaced 2 figures for better readability and updated ensembles, conclusions unchanged. Final, published versio

    Rho decay width from the lattice

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    While the masses of light hadrons have been extensively studied in lattice QCD simulations, there exist only a few exploratory calculations of the strong decay widths of hadronic resonances. We will present preliminary results of a computation of the rho meson width obtained using Nf=2+1N_f=2+1 flavor simulations. The work is based on L\"uscher's formalism and its extension to moving frames.Comment: The XXVIII International Symposium on Lattice Field Theory, June 14-19,2010, Villasimius, Sardinia Ital

    Electromagnetic corrections to light hadron masses

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    At the precision reached in current lattice QCD calculations, electromagnetic effects are becoming numerically relevant. We will present preliminary results for electromagnetic corrections to light hadron masses, based on simulations in which a U(1)\mathrm{U}(1) degree of freedom is superimposed on Nf=2+1N_f=2+1 QCD configurations from the BMW collaboration.Comment: 7 pages, 2 figures, The XXVIII International Symposium on Lattice Field Theory, June 14-19,2010, Villasimius, Sardinia Ital

    Field-Based Experience in Light of Changing Demographics

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    Due to changing demographics of students admitted to the School Psychology Training Program at Marshall University Graduate College, it has become imperative to significantly expand field experiences beginning in the first semester to address the lack of educational background of most of the students entering the program. This organized sequence of field experiences continues throughout the program, parallel to classroom instruction, affording opportunities for students to put theory into practice and to interact with professionals in the field, while also allowing for exposure to the public school environment. The collaborative field experience sequence provides the students with early and continuous feedback on their personal fit with schools as organizations and culminates with the summer enrichment program

    Hadronic vacuum polarization contribution to the anomalous magnetic moments of leptons from first principles

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    We compute the leading, strong-interaction contribution to the anomalous magnetic moment of the electron, muon and tau using lattice quantum chromodynamics (QCD) simulations. Calculations include the effects of uu, dd, ss and cc quarks and are performed directly at the physical values of the quark masses and in volumes of linear extent larger than 6fm6\,\mathrm{fm}. All connected and disconnected Wick contractions are calculated. Continuum limits are carried out using six lattice spacings. We obtain aeLOHVP=189.3(2.6)(5.6)×1014a_e^\mathrm{LO-HVP}=189.3(2.6)(5.6)\times 10^{-14}, aμLOHVP=711.1(7.5)(17.4)×1010a_\mu^\mathrm{LO-HVP}=711.1(7.5)(17.4)\times 10^{-10} and aτLOHVP=341.0(0.8)(3.2)×108a_\tau^\mathrm{LO-HVP}=341.0(0.8)(3.2)\times 10^{-8}, where the first error is statistical and the second is systematic.Comment: 17 pages, 8 figures (in 13 PDF files), RevTeX 4.1. Minor changes to results and to text. References updated. Matches version published in Physical Review Letter
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