Author/Authors :
OPAL Collaboration، نويسنده , , K Ackerstaff، نويسنده , , G Alexander، نويسنده , , J Allison، نويسنده , , N. Altekamp، نويسنده , , K. Ametewee، نويسنده , , K.J. Anderson، نويسنده , , S Anderson، نويسنده , , S Arcelli، نويسنده , , S Asai، نويسنده , , D Axen، نويسنده , , G Azuelos، نويسنده , , A.H. Ball، نويسنده , , E Barberio، نويسنده , , R.J. Barlow، نويسنده , , R. Bartoldus، نويسنده , , J.R. Batley، نويسنده , , J Bechtluft، نويسنده , , C Beeston، نويسنده , , T Behnke، نويسنده , , et al.، نويسنده ,
Abstract :
We have searched for excited states of charged and neutral leptons, e∗, μ∗, τ∗ and ν∗, in e+e− collisions at s=161 GeV using the OPAL detector at LEP. No evidence for their existence was found. With the most common coupling assumptions, the topologies from excited lepton pair production include ℓ+ℓ−γγ and ℓ+ℓ−W+W−, with the subsequent decay of the virtual W bosons. From the analysis of these topologies, 95% confidence level lower mass limits of 79.9 GeV for e∗, 80.0 GeV for μ∗, 79.1 GeV for τ∗, 78.3 GeV for νe∗, 78.9 GeV for νμ∗ and 76.2 GeV for ντ∗ are inferred. From the analysis of W+W− and γγ topologies with missing energy and using alternative coupling assingments which favour charged ℓ∗± and photonic ν∗ decays, 95% confidence level lower mass limits of 77.1 GeV for each ℓ∗± flavour and 77.8 GeV for each ν∗ flavour are inferred. From the analysis of the ℓ+ℓ−γ, ℓ±W∓ and single γ final states expected from excited lepton single production, upper limits on the ratio of the coupling to the compositeness scale, fΛ, are determined for excited lepton masses up to the kinematic limit.
