SINGLET POLARIZATION FUNCTIONS AT O(ALPHA(2)(S)) - ART. NO. 014012

We consider the three-loop singlet diagrams induced by axial-vector, s calar, and pseudoscalar currents. Expansions for small and large exter nal momentum q are presented. They are used in combination with confor mal mapping and Pade approximations in order to arrive at results for the polarization functions valid for all q(2). Results are presented f or the imaginary parts which are directly related to physical quantiti es such as the production of top quarks or the decay of scalar or pseu doscalar Higgs bosons. [S0556-2821(98)03713-8].