248 research outputs found

    Search for neutral heavy leptons produced in ZZ decays

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    Weak isosinglet Neutral Heavy Leptons (Îœm) have been searched for using data collected by the DELPHI detector corresponding to 3.3 × 106 hadronic Z0 decays at LEP1. Four separate searches have been performed, for short-lived Îœm production giving monojet or acollinear jet topologies, and for long-lived Îœm giving detectable secondary vertices or calorimeter clusters. No indication of the existence of these particles has been found, leading to an upper limit for the branching ratio BR(Z0 → ÎœmΜ̄) of about 1.3 × 10-6 at 95% confidence level for Îœm masses between 3.5 and 50 GeV/c2. Outside this range the limit weakens rapidly with the Îœm mass. The results are also interpreted in terms of limits for the single production of excited neutrinos. © Springer-Verlag 1997

    Electroweak parameters of the z0 resonance and the standard model

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    Contains fulltext : 124399.pdf (publisher's version ) (Open Access

    Species diversification – which species should we use?

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    Large detector systems for particle and astroparticle physics; Particle tracking detectors; Gaseous detectors; Calorimeters; Cherenkov detectors; Particle identification methods; Photon detectors for UV. visible and IR photons; Detector alignment and calibration methods; Detector cooling and thermo-stabilization; Detector design and construction technologies and materials. The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems. as established by test beam measurements and simulation studies. is described. © 2008 IOP Publishing Ltd and SISSA
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