0000000000385533

AUTHOR

R. Miguel

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

Search for excited neutrinos in Z decay

1990

Excited neutrinos decaying into a neutrino and a photon are searched for in the ALEPH detector at LEP. No evidence is found for Z decay into vv∗ or v∗v∗ final states. Upper limits are derived on excited neutrino couplings up to excited neutrino masses close to the Z mass. Lower limits on the v∗ mass, independent of the v∗ decay modes, are deduced from the total Z width.

PhysicsNuclear and High Energy PhysicsParticle physicsAlephPhotonPhysics::Instrumentation and DetectorsAstrophysics::High Energy Astrophysical PhenomenaElectron–positron annihilationHigh Energy Physics::PhenomenologyDetectorLower limitNuclear physicsExcited stateHigh Energy Physics::ExperimentNeutrinoParticle Physics - Experiment
researchProduct