7,312 research outputs found

    Heavy Flavor Measurements in ATLAS and CMS

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    We present heavy flavor measurements performed by the ATLAS and CMS Collaborations with data collected at the Large Hadron Collider. The production mechanism of heavy flavor hadrons is discussed as well as lifetime measurements and searches for the rare decay Bs->mumu. The large available statistics of about 5 fb-1 per experiment collected during the year 2011 together with the excellent detector performance allows to perform competitive heavy flavor measurements.Comment: 8 pages, 12 figures, proceedings for Moriond EW 201

    Measurement of alpha_S in e+e- collisions at LEP and JADE

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    Data from e+e- annihilation into hadrons collected by the JADE, the L3 and the OPAL experiment at centre-of-mass energies between 14 GeV and 209 GeV are used to determine the strong coupling alpha_S. Observables in leading order sensitive to alpha_S as well as alpha_S**2 are used. The evolution of alpha_S with respect to the centre-of-mass energy as predicted by QCD is studied and confirmed with high precision. All measurements of alpha_S are consistent with the current world average.Comment: 4 pages, 3 figures, contributed to the Proceedings of ICHEP200

    Reassessing the discovery potential of the B → K*ℓâșℓ⁻ decays in the large-recoil region: SM challenges and BSM opportunities

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    We critically examine the potential to disentangle Standard Model (SM) and New Physics (NP) in B→K∗Ό+Ό−B \to K^* \mu^+\mu^- and B→K∗e+e−B\to K^* e^+ e^- decays, focusing on (i)(i) the LHCb anomaly, (ii)(ii) the search for right-handed currents, and (iii)(iii) lepton-universality violation. Restricting ourselves to the large-recoil region, we advocate a parameterisation of the hadronic matrix elements that separates model-independent information about nonperturbative QCD from the results of model calculations. We clarify how to estimate corrections to the heavy-quark limit that would generate a right-handed (virtual) photon in the b→sÎłb\to s\gamma contribution to the decay. We then apply this approach to the discussion of various sets of observables of increasing theoretical cleanness. First, we show that angular observables in the optimized Pi(â€Č)P_i^{(\prime)} basis are, in general, not robust against the long-distance QCD effects. While a fit to data favours a NP contribution to the semileptonic operators of the type ÎŽC9≃−1.5\delta C_9\simeq-1.5, this comes at a relatively small statistical significance of â‰Č2σ\lesssim2 \sigma, once power corrections are properly accounted for. Second, two of these observables, P1P_1 and P3CPP_3^{CP} are particularly clean at very low q2q^2 and sensitive probes of right-handed quark currents. We discuss their potential to set stringent bounds on the Wilson coefficient C7â€ČC_7^\prime, especially using data of the electronic mode. Finally, in light of the recent hint of lepton-universality violation in B+→K+ℓℓB^+\to K^+\ell\ell, we introduce and investigate new lepton-universality observables involving angular observables of the muonic and electronic modes and their zero crossings, and show that, if the effect is of the size suggested by experiment, these can clearly distinguish between different NP explanations in terms of underlying semileptonic operators.Comment: We recalculated the results with some updated theoretical input parameters which cause mild changes in some central values and a slight increase of the significance of tensions with the SM. Included new Table with full results with errors obtained using Gaussian distributions of the nuisance parameters. Some parts of the discussions have also been improve

    Study of moments of event shapes in e+e- annihilation using JADE data

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    Data from e+e- annihilation into hadrons collected by the JADE experiment at centre-of-mass energies between 14 GeV and 44 GeV were used to study moments of event shape distributions. The data were compared with Monte Carlo models and with predictions from QCD NLO order calculations. The strong coupling constant measured from the moments is alpha_S(M_Z) = 0.1286 +/- 0.0007 (stat) +/- 0.0011 (expt) +/- 0.0022 (had) +/- 0.0068 (theo), alpha_S(M_Z) = 0.1286 +/- 0.0072 (total error), consistent with the world average. However, systematic deficiencies in the QCD NLO order predictions are visible for some of the higher moments.Comment: JADE note 147 submitted as contributed paper to ICHEP 2004, corrected statistical error of 6 observable average and several typo

    Measurement of the Strong Coupling Constant alpha_S from the Four-Jet Rate in e+e- Annihilation using JADE data

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    Data from e+e- annihilation into hadrons collected by the JADE experiment at centre-of-mass energies between 14 GeV and 44 GeV were used to study the four-jet rate as a function of the Durham algorithm's resolution parameter y_cut. The four-jet rate was compared to a QCD NLO order calculations including NLLA resummation of large logarithms. The strong coupling constant measured from the four-jet rate is alpha_S(M_Z) = 0.1169 +/- 0.0004 (stat) +/- 0.0012 (expt) +/- 0.0021 (had) +/- 0.0007 (theo), alpha_S(M_Z) = 0.1169 +/- 0.0026 (total error) in agreement with the world average.Comment: JADE note 146 submitted as contributed paper to ICHEP 200

    Symbolic Activities in Virtual Spaces

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    This paper presents an approach to combine concepts ofsymbolic acting and virtual storytelling with the support ofcooperative processes. We will motivate why symboliclanguages are relevant in the social context of awarenessapplications. We will describe different symbolicpresentations and illustrate their application in three differentprototypes
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