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Aims. We present cosmological constraints from a joint analysis of type Ia supernova (SN Ia) observations obtained by the SDSS-II and SNLS collaborations. The dataset includes several low-redshift samples (z < 0.1), all three seasons from the SDSS-II (0.05 < z < 0.4), and three years from SNLS (0.2 < z < 1), and it totals 740 spectroscopically confirmed type Ia supernovae with high-quality light curves. Methods. We followed the methods and assumptions of the SNLS three-year data analysis except for the following important improvements: 1) the addition of the full SDSS-II spectroscopically-confirmed SN Ia sample in both the training of the SALT2 light-curve model and in the Hubble diagram analysis (374 SNe); 2) intercalibration of the SNLS and SDSS surveys and reduced systematic uncertainties in the photometric calibration, performed blindly with respect to the cosmology analysis; and 3) a thorough investigation of systematic errors associated with the SALT2 modeling of SN Ia light curves. Results. We produce recalibrated SN Ia light curves and associated distances for the SDSS-II and SNLS samples. The large SDSS-II sample provides an effective, independent, low-z anchor for the Hubble diagram and reduces the systematic error from calibration systematics in the low-z SN sample. For a flat ΛCDM cosmology, we find Ω m = 0.295 ± 0.034 (stat+sys), a value consistent with the most recent cosmic microwave background (CMB) measurement from the Planck and WMAP experiments. Our result is 1.8σ (stat+sys) different than the previously published result of SNLS three-year data. The change is due primarily to improvements in the SNLS photometric calibration. When combined with CMB constraints, we measure a constant dark-energy equation of state parameter w = −1.018 ± 0.057 (stat+sys) for a flat universe. Adding baryon acoustic oscillation distance measurements gives similar constraints: w = −1.027 ± 0.055. Our supernova measurements provide the most stringent constraints to date on the nature of dark energy.

We present measurements of the Hubble diagram for 103 Type Ia supernovae (SNe) with redshifts 0.04 < z < 0.42, discovered during the first season (Fall 2005) of the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. These data fill in the redshift "desert" between low-and high-redshift SN Ia surveys. Within the framework of the mlcs2k2 light-curve fitting method, we use the SDSS-II SN sample to infer the mean reddening parameter for host galaxies, R V = 2.18 ± 0.14 stat ± 0.48 syst , and find that the intrinsic distribution of host-galaxy extinction is well fitted by an exponential function, P (A V) = exp(−A V /τ V), with τ V = 0.334 ± 0.088 mag. We combine the SDSS-II measurements with new distance estimates for published SN data from the ESSENCE survey, the Supernova Legacy Survey (SNLS), the Hubble Space Telescope (HST), and a compilation of Nearby SN Ia measurements. A new feature in our analysis is the use of detailed Monte Carlo simulations of all surveys to account for selection biases, including those from spectroscopic targeting. Combining the SN Hubble diagram with measurements of baryon acoustic oscillations from the SDSS Luminous Red Galaxy sample and with cosmic microwave background temperature anisotropy measurements from the Wilkinson Microwave Anisotropy Probe, we estimate the cosmological parameters w and Ω M , assuming a spatially flat cosmological model (FwCDM) with constant dark energy equation of state parameter, w. We also consider constraints upon Ω M and Ω Λ for a cosmological constant model (ΛCDM) with w = −1 and non-zero spatial curvature. For the FwCDM model and the combined sample of 288 SNe Ia,

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We report a measurement of the branching fraction ratios R(D ( * ) ) ofB → D ( * ) τ −ν τ relative tō B → D ( * ) −ν (where = e or µ) using the full Belle data sample of 772 × 10 6 BB pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e + e − collider. The measured values are R(D) = 0.375 ± 0.064(stat.) ± 0.026(syst.) and R(D * ) = 0.293 ± 0.038(stat.) ± 0.015(syst.). The analysis uses hadronic reconstruction of the tag-side B meson and purely leptonic τ decays. The results are consistent with earlier measurements and do not show a significant deviation from the standard model prediction.