Search for Charged Higgs Bosons in e+e- Collisions at \sqrt{s} = 189 GeV

A search for pair-produced charged Higgs bosons is performed with the L3 detector at LEP using data collected at a centre-of-mass energy of 188.6 GeV, corresponding to an integrated luminosity of 176.4 pb^-1. Higgs decays into a charm and a strange quark or into a tau lepton and its associated neutrino are considered. The observed events are consistent with the expectations from Standard Model background processes. A lower limit of 65.5 GeV on the charged Higgs mass is derived at 95 % confidence level, independent of the decay branching ratio Br(H^{+/-} -> tau nu)

Measurement of Triple-Gauge-Boson Couplings of the W Boson at LEP

We report on measurements of the triple-gauge-boson couplings of the W boson in $\mathrm{e^+e^-}$ collisions with the L3 detector at LEP. W-pair, single-W and single-photon events are analysed in a data sample corresponding to a total luminosity of 76.7~pb$^{-1}$ collected at centre-of-mass energies between 161~GeV and 183~GeV. CP-conserving as well as both C- and P-conserving triple-gauge-boson couplings are determined. The results, in good agreement with the Standard-Model expectations, confirm the existence of the self coupling among the electroweak gauge bosons and constrain its structure

Search for anomalous couplings in the Higgs sector at LEP

We search for a Higgs particle with anomalous couplings in the e+e- -> H gamma, e+e- -> HZ and e+e- -> He+e- processes with the L3 detector at LEP. We explore the mass range 70GeV m_H 170GeV using 176pb^-1 of integrated luminosity at a center-of-mass energy of \sqrt{s} = 189GeV. The Higgs decays H -> bb, H -> gamma gamma and H -> Z gamma are considered in the analysis. No evidence for anomalous Higgs production is found. This is interpreted in terms of limits on the anomalous couplings d, d_B, Delta g_1^Z and Delta kappa_gamma. Limits on the Gamma(H -> gamma gamma) and Gamma(H -> Z gamma) partial widths in the explored Higgs mass range are also obtained

Synthesis of 2-azidoethyl α-d-mannopyranoside orthogonally protected and selective deprotections

4 páginas, 1 figura, 2 esquemas.We present the synthesis of a fully orthogonally protected mannosyl glycoside 1 and the corresponding methods for selective deprotections. Mannosyl glycoside 1 contains a functionalized linker at the anomeric position to allow for the attachment of carbohydrate units to scaffolds in order to prepare carbohydrate multivalent systems.We would like to thank FIS (PI030093), for financial supportPeer reviewe

Status of NESTOR, a deep sea neutrino telescope in the Mediterranean

In the last few years a great interest has been expressed for the construction of a Neutrino Astroparticle Physics Laboratory in the Mediterranean. The NESTOR collaboration made important progresses and plans soon to deploy in deep sea a detector with similar to 10(4) m(2) effective surface. This detector will be able not only to demonstrate the validity of the experimental approach but also to start data collection and then real Neutrino Astrophysics. The status of the preparation of the experiment and the future programs are described

NESTOR: a status report

NESTOR is an underwater neutrino astrophysics laboratory to be located in the international waters of the southwest of Greece. The first phase of this experiment is the construction and deployment of one hexagonal tower consisting of 168 optical modules, with effective area of 20000m(2) for E greater than or equal to TeV neutrinos. Over the past few years detailed studies of the site have been carried out while many tests have been performed. The current status of the preparation of the experiment and the future plans will be presented

ASSOCIATED PHOTOPRODUCTION OF A CHARMED MESON AND A CHARMED BARYON

Detailed description of an event in which associated photoproduction of a charmed meson and a charmed baryon has been oserved. The event was recorded in the course of an experiment using nuclear emulsions exposed to the CERN SPS tagged photon beam and coupled to the Omega Prime spectrometer (Experiment WA58). The proper decay time of the charmed meson, identified as a D0bar, is (0.86+/-0.01)x10^(-13) s while the proper decay time of the charmed baryon, identified as a Lambda_c+ is (0.57+/-0.02)x10^(-13) s