427 research outputs found

    Search for charged Higgs bosons in e+e- collisions at energies up to sqrt(s) = 209GeV

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    A search for charged Higgs bosons produced in pairs is performed with data collected at centre-of-mass energies ranging from 189 to 209 GeV by ALEPH at LEP, corresponding to a total luminosity of 629 invpb. The three final states taunutaunu, taunucs and cscs are considered. No evidence for a signal is found and lower limits are set on the mass M_H+ as a function of the branching fraction B(H to taunu). In the framework of a two-Higgs-doublet model, and assuming B(H+ to taunu + B(H+ to cs) = 1 charged Higgs bosons with masses below 79.3 Gev/c2 are excluded at 95% confidence level independently of the branching ratios

    Event shapes and power corrections in e+e- annihilitions

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    Hadronic final states in e+e- annihilitions at centre-of-mass energies from 14GeV up to 189GeV are studied in order to test recent predictions for power corrections to the mean values as well as the distributions of event shape variables.Comment: 3 pages, 3 figures, DIS99 Workshop, Berlin, Germany, April 19-23, 199

    Particle Flow Calorimetry at the ILC

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    One of the most important requirements for a detector at the ILC is good jet energy resolution. It is widely believed that the particle flow approach to calorimetry is the key to achieving the goal of 0.3/sqrt(E[GeV]). This paper describes the current performance of the PandoraPFA particle flow algorithm. For 45 GeV jets in the Tesla TDR detector concept, the ILC jet energy resolution goal is reached. At higher energies the jet energy resolution becomes worse and can be described by the empirical expression: sigma_E/E ~ 0.265/sqrt(E[GeV]) + 1.2x10^{-4}E[GeV].Comment: 5 pages, 2 .eps figures, to appear in Proc. LCWS06, Bangalore, March 200

    B Physics at the Z0 Resonance

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    B physics results from e+ e- annihilation at the Z0 resonance are reviewed. A vast program is summarised, including the study of B+, B0d, B0s and b baryon lifetimes, the time dependence of B0d and B0s oscillations, the width difference in the B0s system, and the measurements of the magnitudes of the CKM matrix elements Vcb and Vub.Comment: 17 pages, 8 figures, presented at the UK Phenomenology Workshop on Heavy Flavour and CP Violation, 17-22 September 200
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