1,497 research outputs found

    Precise Determination of |V{us}| from Lattice Calculations of Pseudoscalar Decay Constants

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    Combining the ratio of experimental kaon and pion decay widths, Gamma(K to mu antineutrino{mu} (gamma)) / Gamma(pi to mu \antineutrino (gamma)), with a recent lattice gauge theory calculation of f{K}/f{pi} provides a precise value for the CKM quark mixing matrix element |V{us}|=0.2236(30) or if 3 generation unitarity is assumed |V{us}|=0.2238(30). Comparison with other determinations of that fundamental parameter, implications, and an outlook for future improvements are given

    Electroweak Radiative Corrections To Polarized M{\o}ller Scattering Asymmetries

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    One loop electroweak radiative corrections to left-right parity violating M{\o}ller scattering (eeeee^-e^-\to e^-e^-) asymmetries are presented. They reduce the standard model (tree level) prediction by 40±3\pm 3 \% where the main shift and uncertainty stem from hadronic vacuum polarization loops. A similar reduction also occurs for the electron-electron atomic parity violating interaction. That effect can be attributed to an increase of sin2θW(q2)\sin^2\theta_W(q^2) by 3%3\% in running from q2=mZ2q^2=m_Z^2 to 0. The sensitivity of the asymmetry to ``new physics'' is also discussed.Comment: 14 pages, Revtex, postscript file including figures is available at ftp://ttpux2.physik.uni-karlsruhe.de/ttp95-14/ttp95-14.ps or via WWW at http://ttpux2.physik.uni-karlsruhe.de/cgi-bin/preprints/ (129.13.102.139

    Enabling Inter-Repository Access Management between iRODS and Fedora

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    4th International Conference on Open RepositoriesThis presentation was part of the session : Conference PresentationsDate: 2009-06-04 08:30 AM – 10:00 AMMany digital repositories have been built using different technologies such as Fedora and the integrated Rule-Oriented Data System (iRODS). This paper analyzes both the Fedora and iRODS technologies to understand how to integrate the two systems to enable cross-repository data sharing. The areas considered include the digital object model, services, management of distributed storage, external data resources, and policy enforcement.National Science Foundatio

    Recent developments in rare kaon decays

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    We discuss issues in rare and radiative kaon decays. The interest is to extract useful short-distance information and uncover underlying dynamics. We emphasize channels where either we can understand non-perturbative aspects of QCD or there is a chance to test the Standard Model.Comment: Invited minireview for Modern Physics Letters A (MPLA), 15 pages, 9 figures, usepackages epsf,colo

    "Dark" Z implications for Parity Violation, Rare Meson Decays, and Higgs Physics

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    General consequences of mass mixing between the ordinary Z boson and a relatively light Z_d boson, the "dark" Z, arising from a U(1)_d gauge symmetry, associated with a hidden sector such as dark matter, are examined. New effects beyond kinetic mixing are emphasized. Z-Z_d mixing introduces a new source of low energy parity violation well explored by possible future atomic parity violation and planned polarized electron scattering experiments. Rare K (B) meson decays into pi (K) l^+ l^- (l = e, mu) and pi (K) nu anti-nu are found to already place tight constraints on the size of Z-Z_d mixing. Those sensitivities can be further improved with future dedicated searches at K and B factories as well as binned studies of existing data. Z-Z_d mixing can also lead to the Higgs decay H -> Z Z_d, followed by Z -> l_1^+ l_1^- and Z_d -> l_2^+ l_2^- or "missing energy", providing a potential hidden sector discovery channel at the LHC. An illustrative realization of these effects in a 2 Higgs doublet model is presented.Comment: Version to appear in PR

    Fermi Constants and ``New Physics''

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    Various precision determinations of the Fermi constant are compared. Included are muon and (leptonic) tau decays as well as indirect prescriptions employing \alpha, m_Z, m_W, \ssthwmzms, \Gamma(Z\to\ell^+\ell^-), and Γ(Zννˉ)\Gamma(Z \to \nu\bar \nu) as input. Their good agreement tests the standard model at the ±0.1\pm 0.1% level and provides stringent constraints on new physics. That utility is illustrated for: heavy neutrino mixing, 2 Higgs doublet models, S, T, and U parameters and excited W±W^{\ast^\pm} bosons (Kaluza-Klein excitations). For the last of those examples, m_{W^\ast}\gsims 2.9 TeV is found.Comment: 14 page
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