Dimitri Yuri Bardin

Bhabha scattering with higher order weak loop corrections

We present a compact incorporation of the weak loop effects in the Bhabha cross section with the accuracy required by the present precision experiments. Special care is taken of the leading 2-loop effects from a heavy top quark which are of the type α2(mt/MZ)4. We find very satisfactory agreement between two independent calculations which are based on different gauges and different renormalizations. The compact formulation in terms of form factors allows a straight-forward implementation into analytic or Monte Carlo QED calculations.

The convolution integral for the forward-backward asymmetry in e+e− annihilation

Abstract The complete convolution integral for the forward-backward asymmetry AFB in e+e− annihilation is obtained in order O (α) with soft photon exponentiation. The influence of these QED corrections on AFB in the vicinity of the Z peak is discussed. The results are used to comment on a recent ad hoc ansatz using convolution weights derived for the total cross section.

Analytic final state corrections with cut for e sup + e sup minus yields massive fermions

In this paper, analytic results for final state corrections to the differential and total cross-section for e{sup +}e{sup {minus}} {yields} massive fermions are presented. In the phase space integration a cut on the photon energy was included. The numerical importance of the obtained results is shown for QED and QCD corrections to {tau}, b and t-quark production. Final state corrections are changed considerably by applying a cut on the photon energy. All results are immediately applicable to theories with several neutral gauge bosons.

Semi-analytical approach to four-fermion production in e+e− annihilation☆

A study of the semi-analytical approach to four-fermion production in e+e− annihilation is presented. We classify all possible four-fermion final states and present results of new calculations for the ‘basic’ processes with the WW, ZZ, and ZH off-shell production together with some examples of ‘background’ processes. The Initial State Radiative corrections are included for the basic processes. Several numerical examples are given in the energy range from LEP 2 up to s = 1 TeV.