Search for a Z' at the Z resonance - L3 Collaboration; Adriani, O.; Aguilar-Benitez, M.; Ahlen, S.; Alcaraz, J.; Aloisio, A.; Alverson, G.; Alviggi, M.G.; Arefiev, A.; Atamanchuk, A.; Baschirotto, A.; Bay, A.; et al. (Elsevier)
The search for an additional heavy gauge boson Z' is described. The models considered are based on either a superstring-motivated E"6 or on a left-right symmetry and assume a minimal Higgs sector. Cross sections and asymmetries measured with the L3 detector in the vicinity of the Z resonance during the 1990 and 1991 running periods are used to determine limits on the Z-Z' gauge boson mixing angle and on the Z' mass. For Z' masses above the direct limits, we obtain the following allowed ranges of the mixing angle, θ"M at the 95% confidence level: -0.004 θ"M 0.015 for the χ model, -0.003 θ"M 0.020 for the ψ model, -0.029 θ"M 0.010 for the η model, -0.002 θ"M 0.020 for the LR model,
http://linkinghub.elsevier.com/retrieve/pii/0370-2693(93)91156-H
Keywords: U