0000000000385538

AUTHOR

Z.l. Zhou

showing 2 related works from this author

Search for a new weakly interacting particle

1991

Abstract A search for events of the type e + e − →l + l − X 0 , where X 0 can be any weakly interacting particle which couples to the Z, has been performed with the ALEPH detector at LEP, by searching for acollinear lepton pairs. Such particles can be excluded up to a mass of 7.0 GeV/c 2 for a value of the ratio of branching fractions, Br( Z →X 0 l + l − )/Br(Z→ l + l − ), greater than 2.5 × 10 −3 if the X 0 has third component of isospin, I 3 greater than 1 2 and decays to a pair of virtual gauge bosons. When this analysis is combined with the previous results of the Higgs particle searches from ALEPH, this limit can be extended to an X 0 mass of 60 GeV/c 2 .

PhysicsNuclear physicsNuclear and High Energy PhysicsAlephParticle physicsGauge bosonIsospinElectron–positron annihilationHigh Energy Physics::PhenomenologyHiggs bosonHigh Energy Physics::ExperimentParticle Physics - ExperimentLepton
researchProduct

Measurement of the B hadron lifetime

1991

The average lifetime of B hadrons has been measured by the ALEPH experiment at LEP. Events containing B hadrons are selected by the identification of leptons with high transverse momentum in hadronic Z decays, and the lifetime is extracted from a fit to the impact parameter distribution of the lepton tracks. From a sample of 1.7×105 hadronic Z decays a lifetime of 1.29±0.06±0.10 ps is measured.

PhysicsNuclear and High Energy PhysicsParticle physicsMesonElectron–positron annihilationHigh Energy Physics::PhenomenologyHadronElementary particleNuclear physicsHigh Energy Physics::ExperimentB mesonImpact parameterNuclear ExperimentALEPH experimentParticle Physics - ExperimentLeptonPhysics Letters B
researchProduct