190,975 research outputs found

    Chiral Meson Physics at Two Loops

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    An overview of Chiral Perturbation Theory calculations in the mesonic sector at the two Loop level is given. Discussed in some detail are the partially quenched case relevant for lattice QCD, the general fitting procedures and ππ\pi\pi,πK\pi K scattering as well as the determination of VusV_{us} and Kℓ3K_{\ell3} decays.Comment: 7 pages, Invited plenary talk presented at the 19th European Few-Body conference, Groningen, The Netherlands, August 23-27, 200

    Vector two-point functions in finite volume using partially quenched chiral perturbation theory

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    We calculate vector-vector correlation functions at two loops using partially quenched chiral perturbation theory including finite volume effects and twisted boundary conditions. We present expressions for the flavor neutral cases and the flavor charged case with equal masses. Using these expressions we give an estimate for the ratio of disconnected to connected contributions for the strange part of the electromagnetic current. We give numerical examples for the effects of partial quenching, finite volume and twisting and suggest the use of different twists to check the size of finite volume effects. The main use of this work is expected to be for lattice QCD calculations of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment.Comment: 31 pages, some sentences added regarding partial twisting, reformatted equations in appendix to make them more legibl

    Chiral Perturbation Theory at Finite Volume and/or with Twisted Boundary Conditions

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    In this talk we discuss a number of ChPT calculations relevant for lattice QCD. These include the finite volume corrections at two-loop order for masses and decay constants. The second part is about hadronic vacuum polarization where we present the two-loop ChPT estimate for the disconnected and strange quark contributions. We also present the finite volume corrections at two-loop order. The final part is the one-loop finite volume with twisted boundary conditions contribution to f+(q2)f_+(q^2) and the full Kâ„“3K_{\ell3} amplitudeComment: 7 pages, talk presented at 34th annual International Symposium on Lattice Field Theory, 24-30 July 2016, University of Southampton, U

    A web-based tool to design and analyze single- and double-stage acceptance sampling plans

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    Acceptance sampling plans are used to determine whether production lots can be accepted or rejected. Existing tools only provide a limited functionality for the two-point design and the risk analysis of such plans. In this article, a web-based tool is presented to study single- and double-stage sampling plans. In contrast to existing solutions, the tool is an interactive applet that is freely available. Analytic properties are derived to support the development of search strategies for the design of double-stage sampling plans that are more efficient and accurate in comparison with existing routines. Several case studies are presented

    Scalar Kinetic Mixing and the Renormalization Group

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    Quantum field theories containing scalar fields with equal quantum numbers allow for a mixed kinetic term in the Lagrangian. It has been argued that this mixing must be taken into consideration when performing renormalization group (RG) analyses of such a theory. However, from the fact that scalar kinetic mixing does not correspond to a physical observable, we show that no extra parameters need to be introduced. Using a toy model, we explicitly derive the 1-loop RG equations (RGEs) in three different renormalization schemes to demonstrate how this issue can be dealt with. In schemes without kinetic mixing, either the fields mix during renormalization to produce non-diagonal anomalous dimensions or the RGEs explicitly depend on the scalar masses. Finally, we show how the different schemes are related to each other by scale dependent field redefinitions.Comment: 7 pages, journal versio
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