Showing papers by "Laurent Duflot published in 1997"
TL;DR: In this article, the 132 pbt -1 of data collected by ALEPH from 1991 to 1994 have been used to analyze η and ω production in τ decays and the following branching fractions have been measured:
Abstract: The 132 pbt - 1 of data collected by ALEPH from 1991 to 1994 have been used to analyze η and ω production in τ decays. The following branching fractions have been measured: \(B\left( {{\tau ^ - } \to {
u _\tau }\omega {h^ - }} \right) = \left( {1.91 \pm 0.07 \pm 0.06} \right) \times {10^{ - 2}},\)\(B\left( {{\tau ^ - } \to {
u _\tau }\omega {h^ - }{\pi ^0}} \right) = \left( {4.3 \pm 0.6 \pm 0.5} \right) \times {10^{ - 3}},\)\(B\left( {{\tau ^ - } \to {
u _\tau }\eta {K^ - }} \right) = \left( {2.9_{ - 1.2}^{ + 1.3} \pm 0.7} \right) \times {10^{ - 4}},\)\(B\left( {{\tau ^ - } \to {
u _\tau }\eta {h^ - }{\pi ^0}} \right) = \left( {1.8 \pm 0.4 \pm 0.2} \right) \times {10^{ - 3}}\) and the 95% C.L. limit B(τ− → ντηπt -) < 6.2 × 10t - 4 has been obtained. The ωπt- and ηπt -π0 rates and dynamics are found in agreement with the predictions made from e+e∼ - annihilation data with the help of isospin invariance (CVC).
54 citations
TL;DR: In this paper, two samples of exclusive semileptonic decays, 579 events and 261 events, were selected from approximately 3.9 million hadronic Z decays collected by the ALEPH detector at LEP.
46 citations
TL;DR: In this paper, the LEP 1 data sample was updated using a lifetime tag and a tag based on the b c hadron mass difference was used to reconstruct the event primary vertex.
37 citations
TL;DR: A measurement of Rb using five mutually exclusive hemisphere tags has been performed by ALEPH using the full LEP1 statistics as discussed by the authors, which is in agreement with the electroweak theory prediction of 0.2158 ± 0.0003.
36 citations
TL;DR: In this paper, the LEP centre-of-mass energy was raised to 161 GeV and pair production of W bosons in e+e− collisions was observed for the first time by LEP experiments, where an integrated luminosity of 11 pb−1 was recorded in the ALEPH detector, in which WW candidate events were observed.
35 citations
TL;DR: In this article, the reaction e(+)e(-) --> HZ is used to search for the Standard Model Higgs boson, the data sample consists of integrated luminosities of 10.9 pb(-1), 1.1 pb (-1), and 9.5 pb(1) collected by the ALEPH experiment at LEP during 1996, at centre-of-mass energies of 161, 170 and 172 GeV, respectively.
31 citations
TL;DR: In this paper, the process e(+)e(-) --> hA is used to search for the Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM), in the b (b) over bar b(b), over bar and tau(+)tau(-)b(b)over bar final states, and no candidate events are found in either of the final states.
27 citations
TL;DR: In this article, a new measurement of the mean lifetime of the tau lepton is presented and three different analysis methods are applied to a sample of 90000 tau pairs, collected in 1993 and 1994 with the ALEPH detector at LEP.
19 citations
TL;DR: In this paper, a search for the B c meson decaying into the channels J ψπ + and Jπl + ν l (l = e or μ ) is performed in a sample of 3.9 million hadronic Z decays collected by the ALEPH detector.
18 citations
TL;DR: In this paper, the branching fraction for D0 → K−π+ was measured with statistics collected by ALEPH from 1991 to 1994, based on the comparison between the reconstructed D ∗+ → D 0 π +, D 0 → K −π+ decay chain and the rate for inclusive soft pion production at low transverse momentum with respect to the nearest jet.
10 citations
TL;DR: In this paper, the ALEPH experiment at LEP at center-of-mass energies of 161 GeV and 172 GeV were analysed to search for sleptons, the supersymmetric partners of leptons.
TL;DR: In this paper, the total cross section and the forward-backward asymmetry for the process e+e− → μ+μ−(nγ) are measured in the energy range 20 −136 GeV by reconstructing the effective centre-of-mass energy after initial state radiation.
TL;DR: In this article, the e+e−→W+W− cross section is measured in a data sample collected by ALEPH at a mean centre-of-mass energy of 172.09 GeV, corresponding to an integrated luminosity of 10.65 pb−1.
TL;DR: In this paper, a measurement of the transverse-transverse and transverse normal τ spin correlations in the decay Z → τ+τ−, CTT and CTN, is presented based on the aplanarity angle of the decay products of both τ leptons.
TL;DR: In this article, a measure based on transverse momentum is shown to exhibit a correlation between the two halves of a hadronic event which cannot be explained by energy-momentum conservation, flavour conservation, the imposition of an event axis or imperfect event reconstruction.
Abstract: Using data obtained with the ALEPH detector at the Z resonance, a measure based on transverse momentum is shown to exhibit a correlation between the two halves of a hadronic event which cannot be explained by energy-momentum conservation, flavour conservation, the imposition of an event axis or imperfect event reconstruction. Two possible explanations based on Monte Carlo models are examined: a) ARIADNE, with the correlation forming early in the parton shower and with the transition from partons to hadrons playing only a minor part; b) JETSET, with the correlation forming at the fragmentation stage. A correlation technique based on a jet cluster analysis is used to make a comparison of the models with the data. It is concluded that both non-perturbative and perturbative effects make important contributions to the observed correlation.