TOPAZ0 - A PROGRAM FOR COMPUTING OBSERVABLES AND FOR FITTING CROSS-SECTIONS AND FORWARD-BACKWARD ASYMMETRIES AROUND THE Z(0) PEAK

The program TOPAZ0, which is designed for computing and fitting cross sections and forward-backward asymmetries of e+e- annihilation into fermion pairs and of Bhabha scattering around the Z0 peak, is described. The various observables are computed over both a completely inclusive experimental set-up and a realistic one, i.e. with cuts on acollinearity, energy or invariant mass and angular acceptance of the outgoing fermions. Pure weak corrections at the one-loop level are included and leading higher-order corrections due to a potentially large top quark mass are taken into account. Depending on the experimental set-up initial state QED corrections are included by a convolution of the weakly corrected kernel distribution with a radiator function or with structure functions, where resummation of soft-photon effects and hard-photon emission up to O(alpha2) are taken into account. Final state QED radiation, even in the presence of kinematical cuts, is treated analytically and exactly at O(alpha) and higher-order contributions are taken into account. QCD effects for the parameters of the Z0 resonance and for s-dependent quantities are included. Recently proposed higher-order corrections, as initial state leptonic and hadronic pair production or O(G(F)2m(t)4), O(alpha(s)G(F)m(t)2), O(alpha(s)3), are taken into account as well. The program structure is highly modular and particular care has been devoted to computing efficiency and speed, both for annihilation and Bhabha channels.