ANALYTIC CALCULATION OF 2-LOOP CORRECTIONS TO HEAVY-QUARK PAIR PRODUCTION VERTICES INDUCED BY LIGHT QUARKS

Non-singlet O(alpha(s)(2)) corrections from light quarks are calculate d analytically for the massive quark-antiquark pair production rates t hrough the vector, axial-vector, scalar and pseudoscalar currents for all energies above the threshold. The results are presented in terms o f the moments of the absorptive part of the vacuum polarization functi on of the light quarks, which allows for an immediate determination of O(alpha(s)(2)) corrections coming from other types of light particles . The kinematic regime close to the threshold is examined, and a compa rison to results based on non-relativistic considerations is carried o ut. (C) 1998 Elsevier Science B.V.