9,817 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

    Reassessing the discovery potential of the B → K*ℓ⁺ℓ⁻ 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 BKμ+μB \to K^* \mu^+\mu^- and BKe+eB\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 bsγb\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()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 δC91.5\delta C_9\simeq-1.5, this comes at a relatively small statistical significance of 2σ\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 C7C_7^\prime, especially using data of the electronic mode. Finally, in light of the recent hint of lepton-universality violation in B+K+B^+\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

    The reaction 2H(p,pp)n in three kinematical configurations at E_p = 16 MeV

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    We measured the cross sections of the 2^2H(p,pp)n breakup reaction at Ep_p=16 MeV in three kinematical configurations: the np final-state interaction (FSI), the co-planar star (CST), and an intermediate-star (IST) geometry. The cross sections are compared with theoretical predictions based on the CD Bonn potential alone and combined with the updated 2π\pi-exchange Tucson-Melbourne three-nucleon force (TM99'), calculated without inclusion of the Coulomb interaction. The resulting excellent agreement between data and pure CD Bonn predictions in the FSI testifies to the smallness of three-nucleon force (3NF) effects as well as the insignificance of the Coulomb force for this particular configuration and energy. The CST also agrees well whereas the IST results show small deviations between measurements and theory seen before in the pd breakup space-star geometries which point to possible Coulomb effects. An additional comparison with EFT predictions (without 3NF) up to order N3^3LO shows excellent agreement in the FSI case and a rather similar agreement as for CD Bonn in the CST and IST situations.Comment: 20 pages, 11 figure

    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

    The ν\nu-cleus experiment: A gram-scale fiducial-volume cryogenic detector for the first detection of coherent neutrino-nucleus scattering

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    We discuss a small-scale experiment, called ν\nu-cleus, for the first detection of coherent neutrino-nucleus scattering by probing nuclear-recoil energies down to the 10 eV-regime. The detector consists of low-threshold CaWO4_4 and Al2_2O3_3 calorimeter arrays with a total mass of about 10 g and several cryogenic veto detectors operated at millikelvin temperatures. Realizing a fiducial volume and a multi-element target, the detector enables active discrimination of γ\gamma, neutron and surface backgrounds. A first prototype Al2_2O3_3 device, operated above ground in a setup without shielding, has achieved an energy threshold of 20{\sim20} eV and further improvements are in reach. A sensitivity study for the detection of coherent neutrino scattering at nuclear power plants shows a unique discovery potential (5σ\sigma) within a measuring time of 2{\lesssim2} weeks. Furthermore, a site at a thermal research reactor and the use of a radioactive neutrino source are investigated. With this technology, real-time monitoring of nuclear power plants is feasible.Comment: 14 pages, 19 figure

    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

    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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