0000000000182106
AUTHOR
P.s. Iversen
Improved measurements of cross sections and asymmetries at the Z0 resonance
During the 1992 running period of the LEP e+e- collider, the DELPHI experiment accumulated approximately 24 pb-1 of data at the Z0 peak. The decays into hadrons and charged leptons have been analysed to give values for the cross sections and leptonic forward-backward asymmetries which are significantly improved with respect to those previously published by the DELPHI collaboration. Incorporating these new data, more precise values for the Z0 resonance parameters are obtained from model-independent fits. The results are interpreted within the framework of the Standard Model, yielding for the top quark mass m(t) = 157(-48)+36(expt.)-20(+19)(Higgs) GeV, and for the effective mixing angle sin2 …
Search for the t and b' quarks in hadronic decays of the Z0 boson
We present a search for the third generation up type quark t and a possible fourth down type quark b' in hadronic Z0 decays observed in DELPHI at the LEP collider. For any scenario with a decay through the charged current or into a charged Higgs with a mass at least 6 GeV/c2 below the t and 3 GeVc2 below the b' mass, we set a lower limit for the t quark mass at 44.0 GeV/c2 and for the b' mass at 44.5 GeV/c2. For specific scenarios the mass limits are slightly higher, e.g. for charged current decays the limits are 44.5 and 45.0 GeV/c2 respectively, where all limits are given at a 95% confidence level. © 1990.
Search for pair production of neutral Higgs bosons in Z$^0$ decays
The pair production of the lightest scalar Higgs boson, h, and a pseudoscalar Higgs boson, A, was searched for in a data sample containing 10 000 hadronic Z0 decays. The search involved both leptonic and purely hadronic decay channels of each Higgs boson. No signal was found, and limits on the Higgs boson masses, in the framework of the minimal supersymmetric extension of the standard model, ar reported up to 35 GeV/c2 at 95% CL, for both tan β > 1 and tan β < 1, where tan β is the ratio of the vacuum expectation values of the two Higgs doublets.