4,338 research outputs found

    Precise Determination of the Charm Quark Mass

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    The determination of the charm quark mass is now possible to 1% from QCD, with lattice QCD pushing the error down below 1%. I will describe the ingredients of this approach and how it can achieve this accuracy. Results for quark mass ratios, m_c/m_s and m_b/m_c, can also be determined to 1% from lattice QCD, allowing accuracy for the heavy quark masses to be leveraged into the light quark sector. I will discuss the prospects for, and importance of, improving results in future calculations.Comment: 13 pages, 5 figures, Proceedings of CHARM201

    Lattice QCD meets experiment in hadron physics

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    We review recent results in lattice QCD from numerical simulations that allow for a much more realistic QCD vacuum than has been possible before. Comparison with experiment for a variety of hadronic quantities gives agreement to within statistical and systematic errors of 3%. We discuss the implications of this for future calculations in lattice QCD, particularly those which will provide input for B factory experiments.Comment: Review talk at HADRON2003, Aschaffenberg, Germany, September 200

    D<sub>s</sub> to Ο† and other transitions from lattice QCD

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    We have studied transitions between vector and pseudoscalar mesons using the HISQ action for the valence quarks. We have calculated all of the axial and vector form factors that appear in the decay rate for D_s -&gt; phi l nu over the full q^2 range and compared them to the shape of the experimental decay distributions. We use nonperturbatively normalised currents for the vector and axial vector currents. The same set up for the three point correlations functions also allow us to study radiative decays and we have calculated the decay rate for J/Psi -&gt; eta_c gamma

    Lattice QCD calculation of the B(s)β†’D(s)βˆ—β„“Ξ½{{B}_{(s)}\to D_{(s)}^{*}\ell{\nu}} form factors at zero recoil and implications for ∣Vcb∣{|V_{cb}|}

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    We present results of a lattice QCD calculation of Bβ†’Dβˆ—B\to D^* and Bsβ†’Dsβˆ—B_s\to D_s^* axial vector matrix elements with both states at rest. These zero recoil matrix elements provide the normalization necessary to infer a value for the CKM matrix element ∣Vcb∣|V_{cb}| from experimental measurements of BΛ‰0β†’Dβˆ—+β„“βˆ’Ξ½Λ‰\bar{B}^0\to D^{*+}\ell^-\bar{\nu} and BΛ‰s0β†’Dsβˆ—+β„“βˆ’Ξ½Λ‰\bar{B}^0_s\to D_s^{*+}\ell^-\bar{\nu} decay. Results are derived from correlation functions computed with highly improved staggered quarks (HISQ) for light, strange, and charm quark propagators, and nonrelativistic QCD for the bottom quark propagator. The calculation of correlation functions employs MILC Collaboration ensembles over a range of three lattice spacings. These gauge field configurations include sea quark effects of charm, strange, and equal-mass up and down quarks. We use ensembles with physically light up and down quarks, as well as heavier values. Our main results are FBβ†’Dβˆ—(1)=0.895Β±0.010statΒ±0.024sys\mathcal{F}^{B\to D^*}(1)= 0.895\pm 0.010_{\mathrm{stat}}\pm{{0.024}_{\mathrm{sys}}} and FBsβ†’Dsβˆ—(1)=0.883Β±0.010statΒ±0.028sys\mathcal{F}^{B_s\to D_s^*}(1)= 0.883\pm 0.010_{\mathrm{stat}}\pm{0.028_{\mathrm{sys}}}. We discuss the consequences for ∣Vcb∣|V_{cb}| in light of recent investigations into the extrapolation of experimental data to zero recoil.Comment: 23 pages. v3: Typos corrected. v2: Improved treatment of finite volume effects. Small change to some results (but smaller than the quoted uncertainties). Version accepted for publication in Phys. Rev.

    Improving pupil group work interaction and dialogue in primary classrooms : Results from a year-long intervention study

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    Findings are reported from a year-long evaluation of the effectiveness of the SPRinG programme relative to a control group. SPRinG aimed to address the wide gap between the potential of group interaction to promote learning and its limited use in schools. The project involved working with teachers to develop strategies for enhancing pupil group-work and dialogue, and to implement a pupil relational and group skills training programme. Video observations were conducted of a sub-sample of pupil groups (31 SPRinG; 29 Control groups) working on a specially designed group decision-making activity undertaken in everyday classroom settings. SPRinG groups displayed higher levels of participation, engagement, active and sustained discussion, high level inferential joint reasoning and lower levels of group disruptive blocking behaviours. We argue that group-work can be successfully implemented into everyday school classrooms, and improve pupil interactions and high level discussion, provided teachers take time to train pupils in relational and group-working skills
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