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Results from a search for neutrinoless double-beta decay (0νββ) of ^{136}Xe are presented using the first year of data taken with the upgraded EXO-200 detector. Relative to previous searches by EXO-200, the energy resolution of the detector has been improved to σ/E=1.23%, the electric field in the drift region has been raised by 50%, and a system to suppress radon in the volume between the cryostat and lead shielding has been implemented. In addition, analysis techniques that improve topological discrimination between 0νββ and background events have been developed. Incorporating these hardware and analysis improvements, the median 90% confidence level 0νββ half-life sensitivity after combining with the full data set acquired before the upgrade has increased twofold to 3.7×10^{25}  yr. No statistically significant evidence for 0νββ is observed, leading to a lower limit on the 0νββ half-life of 1.8×10^{25}  yr at the 90% confidence level.

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With the full data sample of 772 × 10 6 BB pairs recorded by the Belle detector at the KEKB electronpositron collider, the decayB → D Ã τ −ν τ is studied with the hadronic τ decays τ − → π − ν τ and τ − → ρ − ν τ . The τ polarization P τ ðD Ã Þ in two-body hadronic τ decays is measured, as well as the ratio of the branching fractions

We present a determination of the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element |V cb | using the decay B → D ν ( = e, µ) based on 711 fb −1 of e + e − → Υ(4S) data recorded by the Belle detector and containing 772 × 10 6 BB pairs. One B meson in the event is fully reconstructed in a hadronic decay mode while the other, on the signal side, is partially reconstructed from a charged lepton and either a D + or D 0 meson in a total of 23 hadronic decay modes. The isospinaveraged branching fraction of the decay B → D ν is found to be B(B 0 → D − + ν ) = (2.31 ± 0.03(stat) ± 0.11(syst))%. Analyzing the differential decay rate as a function of the hadronic recoil with the parameterization of Caprini, Lellouch and Neubert and using the form-factor prediction G(1) = 1.0541 ± 0.0083 calculated by FNAL/MILC, we obtain ηEW|V cb | = (40.12 ± 1.34) × 10 −3 , where ηEW is the electroweak correction factor. Alternatively, assuming the model-independent form-factor parameterization of Boyd, Grinstein and Lebed and using lattice QCD data from the FNAL/MILC and HPQCD collaborations, we find ηEW|V cb | = (41.10 ± 1.14) × 10 −3 .

We present a new measurement of the Cabibbo-Kobayashi-Maskawa matrix element jV cb j from B 0 → D Ã− l þ ν l decays, reconstructed with the full Belle data set of 711 fb −1 integrated luminosity. Two form factor parametrizations, originally conceived by the Caprini-Lellouch-Neubert (CLN) and the Boyd, Grinstein and Lebed (BGL) groups, are used to extract the product F ð1Þη EW jV cb j and the decay form factors, where F ð1Þ is the normalization factor and η EW is a small electroweak correction. In the CLN parametrization we find F ð1Þη EW jV cb j ¼ ð35.06 AE 0.15 AE 0.56Þ × 10 −3 , ρ 2 ¼ 1.106 AE 0.031 AE 0.007, R 1 ð1Þ ¼ 1.229 AE 0.028 AE 0.009, R 2 ð1Þ ¼ 0.852 AE 0.021 AE 0.006. For the BGL parametrization we obtain F ð1Þη EW jV cb j ¼ ð34.93 AE 0.23 AE 0.59Þ × 10 −3 , which is consistent with the world average when correcting for F ð1Þη EW . The branching fraction of B 0 → D Ã− l þ ν l is measured to be BðB 0 → D Ã− l þ ν l Þ ¼ ð4.90 AE 0.02 AE 0.16Þ%. We also present a new test of lepton flavor universality violation in semileptonic B decays, BðB 0 →D Ã− e þ νÞ BðB 0 →D Ã− μ þ νÞ ¼ 1.01 AE 0.01 AE 0.03. The errors quoted correspond to the statistical and systematic uncertainties, respectively. This is the most precise measurement of F ð1Þη EW jV cb j and form factors to date and the first experimental study of the BGL form factor parametrization in an experimental measurement.