Five-loop vacuum polarization in pQCD: O(m_q^2α_s^4 n_f^2) contribution
arXiv:hep-ph/0212303 · doi:10.1016/S0370-2693(03)00186-2
Abstract
We present the analytical calculation of the contribution of order m_q^2 α_s^4 n_f^2 to the absorptive part of the vacuum polarization function of vector currents. This term constitutes an important gauge-invariant part of the full O(m_q^2 alpha_s^4) correction to the total cross-section of e^+ e^- annihilation into hadrons. The results are compared to predictions following from various optimization schemes.
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