2,716 research outputs found

    Identifizierung von ökol. u. konv. Anbauvarianten bei DOK-Weizen mittels Fluoreszenz-Anregungs-Spektroskopie

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    At coded samples of wheat out of the DOK-trial of FiBL (Switzerland) it was possible to identify the organic and conventional grown variants. The method used was fluorescence-excitation-spectroscopy of whole samples. It was also possible to show differences between biodynamic and organic variants

    Die Bestimmung des Physiologischen Aminosäurenstatus von Möhren und Weizen zur Unterscheidung ökol. und konv. Anbauvarianten

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    A procedure for the differentiation and identification of organic versus conventional grown crop is described. The validated (ISO 17025) procedure is based on the precise Determination of the N-Metabolom of the cultivated plant. With this procedure it was possible to distinguish organically from conventionally grown crops

    Bubble Shape Oscillations and the Onset of Sonoluminescence

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    An air bubble trapped in water by an oscillating acoustic field undergoes either radial or nonspherical pulsations depending on the strength of the forcing pressure. Two different instability mechanisms (the Rayleigh--Taylor instability and parametric instability) cause deviations from sphericity. Distinguishing these mechanisms allows explanation of many features of recent experiments on sonoluminescence, and suggests methods for finding sonoluminescence in different parameter regimes.Comment: Phys. Rev. Lett., in pres

    Measurement of the Branching Fraction of the Decay B+π+π+ν\boldsymbol{B^{+}\to\pi^{+}\pi^{-}\ell^{+}\nu_\ell} in Fully Reconstructed Events at Belle

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    We present an analysis of the exclusive B+π+π+νB^{+}\to\pi^{+}\pi^{-}\ell^{+}\nu_{\ell} decay, where \ell represents an electron or a muon, with the assumption of charge-conjugation symmetry and lepton universality. The analysis uses the full Υ(4S)\Upsilon(4S) data sample collected by the Belle detector, corresponding to 711 fb1^{-1} of integrated luminosity. We select the events by fully reconstructing one BB meson in hadronic decay modes, subsequently determining the properties of the other BB meson. We extract the signal yields using a binned maximum-likelihood fit to the missing-mass squared distribution in bins of the invariant mass of the two pions or the momentum transfer squared. We measure a total branching fraction of B(B+π+π+ν)=[22.71.6+1.9(stat)±3.5(syst)]×105{{\cal B}(B^{+}\to \pi^{+}\pi^{-}\ell^{+}\nu_{\ell})= [22.7 ^{+1.9}_{-1.6} (\mathrm{stat}) \pm 3.5(\mathrm{syst}) ]\times 10^{-5}}, where the uncertainties are statistical and systematic, respectively. This result is the first reported measurement of this decay.Comment: 23 pages, 19 figure

    Inclusive study of bottomonium production in association with an η\eta meson in e+ee^+e^- annihilations near Υ(5S)\Upsilon(5S)

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    We study bottomonium production in association with an η\eta meson in e+ee^+e^- annihilations near the Υ(5S)\Upsilon(5S), at a center of mass energy of s=10.866\sqrt{s}=10.866\,GeV. The results are based on the 121.4121.4\,fb1^{-1} data sample collected by the Belle experiment at the asymmetric energy KEKB collider. Only the η\eta meson is reconstructed and the missing-mass spectrum of η\eta candidates is investigated. We observe the e+eηΥJ(1D)e^+e^-\to\eta\Upsilon_J(1D) process and find evidence for the e+eηΥ(2S)e^+e^-\to\eta\Upsilon(2S) process, while no significant signals of Υ(1S)\Upsilon(1S), hb(1P)h_b(1P), nor hb(2P)h_b(2P) are found. Cross sections for the studied processes are reported.Comment: Submitted to EPJ-

    The Time Structure of Hadronic Showers in highly granular Calorimeters with Tungsten and Steel Absorbers

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    The intrinsic time structure of hadronic showers influences the timing capability and the required integration time of hadronic calorimeters in particle physics experiments, and depends on the active medium and on the absorber of the calorimeter. With the CALICE T3B experiment, a setup of 15 small plastic scintillator tiles read out with Silicon Photomultipliers, the time structure of showers is measured on a statistical basis with high spatial and temporal resolution in sampling calorimeters with tungsten and steel absorbers. The results are compared to GEANT4 (version 9.4 patch 03) simulations with different hadronic physics models. These comparisons demonstrate the importance of using high precision treatment of low-energy neutrons for tungsten absorbers, while an overall good agreement between data and simulations for all considered models is observed for steel.Comment: 24 pages including author list, 9 figures, published in JINS

    Measurement of the CKM Matrix Element Vcb|V_{cb}| from B0D+νB^{0} \to D^{*-} \ell^+ \nu_\ell at Belle

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    We present a new measurement of the CKM matrix element Vcb|V_{cb}| from B0D+νB^{0} \to D^{*-} \ell^+ \nu_\ell decays, reconstructed with the full Belle data set of 711fb1711 \, \rm fb^{-1} integrated luminosity. Two form factor parameterizations, originally conceived by the Caprini-Lellouch-Neubert (CLN) and the Boyd, Grinstein and Lebed (BGL) groups, are used to extract the product F(1)ηEWVcb\mathcal{F}(1)\eta_{\rm EW}|V_{cb}| and the decay form factors, where F(1)\mathcal{F}(1) is the normalization factor and ηEW\eta_{\rm EW} is a small electroweak correction. In the CLN parameterization we find F(1)ηEWVcb=(35.06±0.15±0.56)×103\mathcal{F}(1)\eta_{\rm EW}|V_{cb}| = (35.06 \pm 0.15 \pm 0.56) \times 10^{-3}, ρ2=1.106±0.031±0.007\rho^{2}=1.106 \pm 0.031 \pm 0.007, R1(1)=1.229±0.028±0.009R_{1}(1)=1.229 \pm 0.028 \pm 0.009, R2(1)=0.852±0.021±0.006R_{2}(1)=0.852 \pm 0.021 \pm 0.006. For the BGL parameterization we obtain F(1)ηEWVcb=(34.93±0.23±0.59)×103\mathcal{F}(1)\eta_{\rm EW}|V_{cb}|= (34.93 \pm 0.23 \pm 0.59)\times 10^{-3}, which is consistent with the World Average when correcting for F(1)ηEW\mathcal{F}(1)\eta_{\rm EW}. The branching fraction of B0D+νB^{0} \to D^{*-} \ell^+ \nu_\ell is measured to be B(B0D+ν)=(4.90±0.02±0.16)%\mathcal{B}(B^{0}\rightarrow D^{*-}\ell^{+}\nu_{\ell}) = (4.90 \pm 0.02 \pm 0.16)\%. We also present a new test of lepton flavor universality violation in semileptonic BB decays, B(B0De+ν)B(B0Dμ+ν)=1.01±0.01±0.03 \frac{{\cal B }(B^0 \to D^{*-} e^+ \nu)}{{\cal B }(B^0 \to D^{*-} \mu^+ \nu)} = 1.01 \pm 0.01 \pm 0.03~. The errors correspond to the statistical and systematic uncertainties respectively. This is the most precise measurement of F(1)ηEWVcb\mathcal{F}(1)\eta_{\rm EW}|V_{cb}| and form factors to date and the first experimental study of the BGL form factor parameterization in an experimental measurement

    Study of Excited Ξc\Xi_c States Decaying into Ξc0\Xi_c^0 and Ξc+\Xi_c^+ Baryons

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    Using a data sample of 980 fb1{\rm fb}^{-1} of e+ee^+e^- annihilation data taken with the Belle detector operating at the KEKB asymmetric-energy e+ee^+e^- collider, we report the results of a study of excited Ξc\Xi_c states that decay, via the emission of photons and/or charged pions, into Ξc0\Xi_c^0 or Ξc+\Xi_c^+ ground state charmed-strange baryons. We present new measurements of the masses of all members of the Ξc\Xi_c^{\prime}, Ξc(2645)\Xi_c(2645), Ξc(2790)\Xi_c(2790), Ξc(2815)\Xi_c(2815), and Ξc(2980)\Xi_c(2980) isodoublets, measurements of the intrinsic widths of those that decay strongly, and evidence of previously unknown transitions.Comment: Submitted to PR

    Measurement of eta_c(1S), eta_c(2S) and non-resonant eta' pi+ pi- production via two-photon collisions

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    We report the measurement of gamma gamma to eta_c(1S), eta_c(2S) to eta' pi+ pi- with eta' decays to gamma rho and eta pi+ pi- using 941 fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The eta_c(1S) mass and width are measured to be M = [2984.6\pm0.7 (stat.)\pm2.2 (syst.)] MeV/c^{2} and \Gamma = [30.8^{+2.3}_{-2.2}~(stat.) \pm 2.5~(syst.)] MeV, respectively. First observation of eta_c(2S) to eta' pi+ pi- with a significance of 5.5sigma including systematic error is obtained, and the eta_c(2S) mass is measured to be M = [3635.1\pm3.7~(stat.)\pm2.9~(syst.)] MeV/c^{2}. The products of the two-photon decay width and branching fraction (B) of decays to eta'pi+ pi- are determined to be \Gamma_{gamma gamma}B = [65.4\pm2.6~(stat.)\pm6.9~(syst.)] eV for eta_c(1S) and [5.6^{+1.2}_{-1.1}~(stat.)\pm1.1~(syst.)] eV for eta_c(2S). A new decay mode for the eta_c(1S) to eta'f_0(2080) with f_0(2080) to pi+ pi- is observed with a statistical significance of 20sigma. The f_0(2080) mass and width are determined to be M = [2083^{+63}_{-66}~(stat.)\pm 32~(syst.)] MeV/c^{2} and \Gamma = [178^{+60}_{-178}~(stat.) \pm 55~(syst.)] MeV. The cross sections for gamma gamma to eta' pi+ pi- and eta'f_{2}(1270) are measured for the first time.Comment: 19 pages, 14 figure
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