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)

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

A partial-wave analysis of the 3π system in the reaction K-p → π+π-π0 Λ at 4.2 GeV/c

A partial-wave analysis of the (3π)0 system produced peripherally in the reaction K-p → π+π-π0 Λ at 4.2 GeV/c is presented. The observation of the weak Λ decay allows a determination of all the transversity production amplitudes except for two phases. The production of known resonances having decay modes other than 3π is used to test the isobar model ansatz. Significant ω(783), φ(1020) and A2(1310) production is observed. The spin parity of the ω*(1675) is established as 3-. No evidence for production of other resonances, such as axial vector-mesons, is found. © 1977

π - ω interference in the reactions K- p → π+ π- (Λ, ε{lunate}0) at 4.2 GeV/ c

π - ω interference is studied in the reactions K- p → π+ π- (Λ0, ε{lunate}) at 4.2 GeV/c using data from a high statistics experiments in the CERN 2m HBC. The phenomenon is analysed in terms of the conventional formalism as well as in terms of a new model for π - ω interference proposed by Earles and Srivastava. Satisfactory agreement with the data is found for both models. The rate of ω → 2π obtained in the latter model is in agreement with the VMD (Vector Meson Dominance) prediction for ω → γ → ρ{variant} → 2π. © 1977

Ω- produced in K-p reactions at 4.2 GeV/c

Forty Ω- events have been observed in a large (133 events/βb) experiment at 4.2 GeV/c incident K- momentum. Thirty nine of the events come from the three-body reaction K-p→Ω-K+K0. The Ω- is mainly produced in the forward hemisphere (direction of the incident K-). The lifetime is measured to be τ = (0.75 +0.14-0.11 × 10-10 sec substantially less than the Particle Data Group value of (1.3 -0.3+0.2) × 10-10 sec. The mass is determined to be 1671.7 ± 0.6 MeV, in good agreement with other determinations. The decay asymmetry parameter α (for the decay mode Ω- → ΛK-) is found to be -0.2 ± 0.4. © 1978

Measurement of hadron and lepton-pair production at 161 GeV<root s<172 GeV at LEP

Contains fulltext : 26256.pdf (publisher's version ) (Open Access

A Measurement of Pi-Polarization at Lep

Contains fulltext : 26223.pdf (publisher's version ) (Open Access

Electroweak parameters of the z0 resonance and the standard model

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