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

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

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

Lepton non-universality at LEP and charged Higgs

A recent analysis of the LEP data shows an interesting deviation from lepton universality in W boson decays. An excess at the level of 2.8 sigma is found in the tau mode branching ratio with respect to the other two modes. It is suggested that this seeming lepton non-universality might stem from pair production of charged Higgs bosons almost degenerate with W, that preferentially decay to heavy fermions. It is shown that the deviation can be reduced to 1.4 sigma in two Higgs doublet model I without any conflict with the existing direct or indirect constraints. This conclusion is largely independent of tan beta, the ratio of Higgs vacuum expectation values. This scenario can be tested at the forthcoming international linear collider.Comment: 16 pages, published version with minor change