The precision data on Z boson decays from LEP-I and SLC colliders are compared with the predictions based on the minimal standard theory. The Born approximation of the theory is based on three most accurately known observables: G - the four fermion coupling constant of muon decay, mZ - the mass of the Z boson, and (mZ) - the value of the running fine structure constant at the scale of mZ. The electroweak loop corrections are expressed, in addition, in terms of the masses of higgs, mH, of the top and bottom quarks, mt and mb, and of the strong interaction constant s(mZ). The main emphasis of the review is focused on the one-electroweak-loop approximation. Two electroweak loops have been calculated in the literature only partly. Possible manifestations of new physics are briefly discussed.
Document Type: Miscellaneous
ITEP, 117218 Moscow, Russia
ITEP and CPPM, CNRS/IN2P3 - Univ. Mediterranée, Marseille, France
ITEP and INFN, Sezione di Ferrara, Italy
Publication date: September 1, 1999