54 research outputs found

    Building in Hongkong. Field Excursion of the Department of Civil Engineering of the HTWG Konstanz 2012

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    Hongkong steht als Welthandelsmetropole auch für Superlative des Bauens. Dies gilt für die in britischer Zeit errichteten Bauten, aber auch für die nach der Übergabe an China entstandenen Hochhäuser und Brückenbauwerke. Der Exkursionsbericht der Fakultät Bauingenieurwesen der HTWG Konstanz gibt einen Eindruck von diesen Aktivitäten. Er schildert Brücken- und Hochhausbauten, Tunnelbaustellen und die Baustelle eines Klärschlammverbrennungswerks, die während einer Exkursionswoche im September 2012 besichtigt wurden. Darüber hinaus gibt er einen Einblick in die wirtschaftliche Dynamik der Stadt.As a global metropolis Hongkong also stands for outstanding building activities. The report depicts the impressions during a student field excursion of the Faculty of Civil Engineering of the University of Applied Sciences Konstanz, Germany, to construction sites in Hongkong in September 2012

    Search for an Invisibly Decaying Z\u27 Boson at Belle II in e⁺e⁻ → μ⁺μ⁻(e±^{\pm}μ^{\mp}) Plus Missing Energy Final States

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    Erratum: The Belle II Physics Book (Progress of Theoretical and Experimental Physics (2019) 2019 (123C01) DOI: 10.1093/ptep/ptz106)

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    The Belle II Physics Book

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    We present the physics program of the Belle II experiment, located on the intensity frontier SuperKEKB e+ee^+e^- collider. Belle II collected its first collisions in 2018, and is expected to operate for the next decade. It is anticipated to collect 50/ab of collision data over its lifetime. This book is the outcome of a joint effort of Belle II collaborators and theorists through the Belle II theory interface platform (B2TiP), an effort that commenced in 2014. The aim of B2TiP was to elucidate the potential impacts of the Belle II program, which includes a wide scope of physics topics: B physics, charm, tau, quarkonium, electroweak precision measurements and dark sector searches. It is composed of nine working groups (WGs), which are coordinated by teams of theorist and experimentalists conveners: Semileptonic and leptonic B decays, Radiative and Electroweak penguins, phi_1 and phi_2 (time-dependent CP violation) measurements, phi_3 measurements, Charmless hadronic B decay, Charm, Quarkonium(like), tau and low-multiplicity processes, new physics and global fit analyses. This book highlights "golden- and silver-channels", i.e. those that would have the highest potential impact in the field. Theorists scrutinised the role of those measurements and estimated the respective theoretical uncertainties, achievable now as well as prospects for the future. Experimentalists investigated the expected improvements with the large dataset expected from Belle II, taking into account improved performance from the upgraded detector.Comment: 689 page

    Measurement of the integrated luminosity of the Phase 2 data of the Belle II experiment

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    From April to July 2018, a data sample at the peak energy of the γ(4S) resonance was collected with the Belle II detector at the SuperKEKB electron-positron collider. This is the first data sample of the Belle II experiment. Using Bhabha and digamma events, we measure the integrated luminosity of the data sample to be (496.3 ± 0.3 ± 3.0) pb-1, where the first uncertainty is statistical and the second is systematic. This work provides a basis for future luminosity measurements at Belle II

    Measurements of the branching fractions for BKγB \to K^{*}\gamma decays at Belle II

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    This paper reports a study of BKγB \to K^{*}\gamma decays using 62.8±0.662.8\pm 0.6 fb1^{-1} of data collected during 2019--2020 by the Belle II experiment at the SuperKEKB e+ee^{+}e^{-} asymmetric-energy collider, corresponding to (68.2±0.8)×106(68.2 \pm 0.8) \times 10^6 BBB\overline{B} events. We find 454±28454 \pm 28, 50±1050 \pm 10, 169±18169 \pm 18, and 160±17160 \pm 17 signal events in the decay modes B0K0[K+π]γB^{0} \to K^{*0}[K^{+}\pi^{-}]\gamma, B0K0[KS0π0]γB^{0} \to K^{*0}[K^0_{\rm S}\pi^{0}]\gamma, B+K+[K+π0]γB^{+} \to K^{*+}[K^{+}\pi^{0}]\gamma, and B+K+[K+π0]γB^{+} \to K^{*+}[K^{+}\pi^{0}]\gamma, respectively. The uncertainties quoted for the signal yield are statistical only. We report the branching fractions of these decays: B[B0K0[K+π]γ]=(4.5±0.3±0.2)×105,\mathcal{B} [B^{0} \to K^{*0}[K^{+}\pi^{-}]\gamma] = (4.5 \pm 0.3 \pm 0.2) \times 10^{-5}, B[B0K0[KS0π0]γ]=(4.4±0.9±0.6)×105,\mathcal{B} [B^{0} \to K^{*0}[K^0_{\rm S}\pi^{0}]\gamma] = (4.4 \pm 0.9 \pm 0.6) \times 10^{-5}, B[B+K+[K+π0]γ]=(5.0±0.5±0.4)×105, and\mathcal{B} [B^{+} \to K^{*+}[K^{+}\pi^{0}]\gamma] = (5.0 \pm 0.5 \pm 0.4)\times 10^{-5},\text{ and} B[B+K+[KS0π+]γ]=(5.4±0.6±0.4)×105,\mathcal{B} [B^{+} \to K^{*+}[K^0_{\rm S}\pi^{+}]\gamma] = (5.4 \pm 0.6 \pm 0.4) \times 10^{-5}, where the first uncertainty is statistical, and the second is systematic. The results are consistent with world-average values

    Angular analysis of B+ρ+ρ0B^+ \to \rho^+\rho^0 decays reconstructed in 2019, 2020, and 2021 Belle II data

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    We report on a Belle II measurement of the branching fraction (B\mathcal{B}), longitudinal polarization fraction (fLf_L), and CP asymmetry (ACP\mathcal{A}_{CP}) of B+ρ+ρ0B^+\to \rho^+\rho^0 decays. We reconstruct B+ρ+(π+π0(γγ))ρ0(π+π)B^+\to \rho^+(\to \pi^+\pi^0(\to \gamma\gamma))\rho^0(\to \pi^+\pi^-) decays in a sample of SuperKEKB electron-positron collisions collected by the Belle II experiment in 2019, 2020, and 2021 at the Υ\Upsilon(4S) resonance and corresponding to 190 fb1^{-1} of integrated luminosity. We fit the distributions of the difference between expected and observed BB candidate energy, continuum-suppression discriminant, dipion masses, and decay angles of the selected samples, to determine a signal yield of 345±31345 \pm 31 events. The signal yields are corrected for efficiencies determined from simulation and control data samples to obtain $\mathcal{B}(B^+ \to \rho^+\rho^0) = [23.2^{+\ 2.2}_{-\ 2.1} (\rm stat) \pm 2.7 (\rm syst)]\times 10^{-6},, f_L = 0.943 ^{+\ 0.035}_{-\ 0.033} (\rm stat)\pm 0.027(\rm syst),and, and \mathcal{A}_{CP}=-0.069 \pm 0.068(\rm stat) \pm 0.060 (\rm syst).Theresultsagreewithpreviousmeasurements.Thisisthefirstmeasurementof. The results agree with previous measurements. This is the first measurement of \mathcal{A}_{CP}in in B^+\to \rho^+\rho^0$ decays reported by Belle II

    Measurement of the branching fractions and CPCP asymmetries of B+π+π0B^+ \rightarrow \pi^+ \pi^0 and B+K+π0B^+ \rightarrow K^+ \pi^0 decays in 2019-2021 Belle II data

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    We determine the branching fractions B{\mathcal{B}} and CPCP asymmetries ACP{\mathcal{A}_{{\it CP}}} of the decays B+π+π0B^+ \rightarrow \pi^+ \pi^0 and B+K+π0B^+ \rightarrow K^+ \pi^0. The results are based on a data set containing 198 million bottom-antibottom meson pairs corresponding to an integrated luminosity of 190  fb1190\;\text{fb}^{-1} recorded by the Belle II detector in energy-asymmetric electron-positron collisions at the Υ(4S)\Upsilon (4S) resonance. We measure B(B+π+π0)=(6.12±0.53±0.53)×106{\mathcal{B}(B^+ \rightarrow \pi^+ \pi^0) = (6.12 \pm 0.53 \pm 0.53)\times 10^{-6}}, B(B+K+π0)=(14.30±0.69±0.79)×106{\mathcal{B}(B^+ \rightarrow K^+ \pi^0) = (14.30 \pm 0.69 \pm 0.79)\times 10^{-6}}, ACP(B+π+π0)=0.085±0.085±0.019{\mathcal{A}_{{\it CP}}(B^+ \rightarrow \pi^+ \pi^0) = -0.085 \pm 0.085 \pm 0.019}, and ACP(B+K+π0)=0.014±0.047±0.010{\mathcal{A}_{{\it CP}}(B^+ \rightarrow K^+ \pi^0) = 0.014 \pm 0.047 \pm 0.010}, where the first uncertainties are statistical and the second are systematic. These results improve a previous Belle II measurement and agree with the world averages
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