3,172 research outputs found

    Turbulent boundary layer around a group of obstacles in the direction of flow

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    Results of an investigation of a boundary layer in a turbulent flow on the surface of a wall having a group of obstacles on the path of flow are presented with regard to the mean velocity field, velocity distribution of the two dimensional flow, wall surface shear stresses and Reynolds stresses measured in a downstream cross section where an interference of boundary layers takes place in a flow around adjacent obstacles arranged on the path of flow

    Measurement of CP violating asymmetries in B^0 -> K^+K^- K^0_S decays with a time-dependent Dalitz approach

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    We report a measurement of CPCP violating asymmetries in B0(B0)K+KKS0B^0(\overline{B}^0) \to K^+ K^- K^0_S decays with a time-dependent Dalitz approach. This analysis is based on a data sample of 657×106657\times 10^6 BBB\overline{B} pairs accumulated at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ee^+e^- collider. As the result of an unbinned maximum likelihood fit to the selected candidates, the mixing-induced and direct CPCP violation parameters, ϕ1eff\phi^{\rm eff}_1 and ACP{\cal A}_{CP} are obtained for B0ϕ(1020)KS0B^0 \to \phi(1020) K^0_S, B0f0(980)KS0B^0 \to f_0(980) K^0_S and other B0K+KKS0B^0 \to K^+ K^- K^0_S decays. We find four solutions that describe the data. There are \{eqnarray*} \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (32.2 \pm 9.0 \pm 2.6 \pm 1.4)^{\circ}; \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (26.2 \pm 8.8 \pm 2.7 \pm 1.2)^{\circ};\\ \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (27.3 \pm 8.6 \pm 2.8 \pm 1.3)^{\circ}\; {\rm and}\\ \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (24.3 \pm 8.0 \pm 2.9 \pm 5.2)^{\circ}.{eqnarray*}\ The values for the CPCP violating phase in B0ϕ(1020)KS0B^0\to \phi(1020) K^0_S are similar but other properties of the Dalitz plot are quite different for the four solutions. These four solutions have consistent ϕ1eff\phi^{\rm eff}_1 values for all three BB meson decay channels and none of them deviates significantly from the values measured in B(ccˉ)K0B \to (c\bar{c}) K^0 decays with the currently available statistics. In addition, we find no significant direct CPCP violation.Comment: submitted to PR

    Measurement of CP violating asymmetries in B^0 -> K^+K^- K^0_S decays with a time-dependent Dalitz approach

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    We report a measurement of CPCP violating asymmetries in B0(B0)K+KKS0B^0(\overline{B}^0) \to K^+ K^- K^0_S decays with a time-dependent Dalitz approach. This analysis is based on a data sample of 657×106657\times 10^6 BBB\overline{B} pairs accumulated at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ee^+e^- collider. As the result of an unbinned maximum likelihood fit to the selected candidates, the mixing-induced and direct CPCP violation parameters, ϕ1eff\phi^{\rm eff}_1 and ACP{\cal A}_{CP} are obtained for B0ϕ(1020)KS0B^0 \to \phi(1020) K^0_S, B0f0(980)KS0B^0 \to f_0(980) K^0_S and other B0K+KKS0B^0 \to K^+ K^- K^0_S decays. We find four solutions that describe the data. There are \{eqnarray*} \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (32.2 \pm 9.0 \pm 2.6 \pm 1.4)^{\circ}; \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (26.2 \pm 8.8 \pm 2.7 \pm 1.2)^{\circ};\\ \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (27.3 \pm 8.6 \pm 2.8 \pm 1.3)^{\circ}\; {\rm and}\\ \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (24.3 \pm 8.0 \pm 2.9 \pm 5.2)^{\circ}.{eqnarray*}\ The values for the CPCP violating phase in B0ϕ(1020)KS0B^0\to \phi(1020) K^0_S are similar but other properties of the Dalitz plot are quite different for the four solutions. These four solutions have consistent ϕ1eff\phi^{\rm eff}_1 values for all three BB meson decay channels and none of them deviates significantly from the values measured in B(ccˉ)K0B \to (c\bar{c}) K^0 decays with the currently available statistics. In addition, we find no significant direct CPCP violation.Comment: submitted to PR

    Search for Time-Dependent CPT Violation in Hadronic and Semileptonic B Decays

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    We report a new sensitive search for CPT violation, which includes improved measurements of the CPT-violating parameter z and the total decay-width difference normalized to the averaged width DeltaGamma_d/Gamma_d of the two Bd mass eigenstates. The results are based on a data sample of 535 x 10^6 BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We obtain Re(z) = [+1.9 +/- 3.7 (stat) +/- 3.3 (syst)] x 10^{-2}, Im(z) = [-5.7 +/- 3.3 (stat) +/- 3.3 (syst)] x 10^{-3}, and DeltaGamma_d/Gamma_d = [-1.7 +/- 1.8 (stat) +/- 1.1 (syst)] x 10^{-2}, all of which are consistent with zero. This is the most precise single measurement of these parameters in the neutral B-meson system to date.Comment: 7 pages, 3 figures, 2 tables, LaTeX; addition of supplemental information, corrections of typos, results unchange

    Measurement of Time-Dependent CP-Violating Parameters in B0 -> K0S K0S decays

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    We report a measurement of the CP-violating parameters in B0->K0S K0S decays based on a data sample of 657 million BBbar pairs collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. In this study, one neutral B meson is fully reconstructed in the B0->K0S K0S decay mode, and the flavor of the accompanying B meson is identified by its decay products. The CP-violating parameters are measured from the asymmetry in the distributions of the proper-time interval between the two B decays: S = -0.38 +0.69-0.77(stat) +-0.09(syst) and A = -0.38 +-0.38(stat) +-0.05(syst).Comment: 5pages, 2figures, submitted to PR

    Angular analysis of B0K(892)0+B^0 \to K^\ast(892)^0 \ell^+ \ell^-

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    We present a measurement of angular observables, P4P_4', P5P_5', P6P_6', P8P_8', in the decay B0K(892)0+B^0 \to K^\ast(892)^0 \ell^+ \ell^-, where +\ell^+\ell^- is either e+ee^+e^- or μ+μ\mu^+\mu^-. The analysis is performed on a data sample corresponding to an integrated luminosity of 711 fb1711~\mathrm{fb}^{-1} containing 772×106772\times 10^{6} BBˉB\bar B pairs, collected at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the asymmetric-energy e+ee^+e^- collider KEKB. Four angular observables, P4,5,6,8P_{4,5,6,8}' are extracted in five bins of the invariant mass squared of the lepton system, q2q^2. We compare our results for P4,5,6,8P_{4,5,6,8}' with Standard Model predictions including the q2q^2 region in which the LHCb collaboration reported the so-called P5P_5' anomaly.Comment: Conference paper for LHC Ski 2016. SM prediction for P6P_{6}' corrected and reference for arXiv:1207.2753 adde
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