The two-loop massive operator matrix elements for the fermionic local twist--2 operators with external massive fermion lines in Quantum Electrodynamics (QED) are calculated up to the constant terms in the dimensional parameter ϵ=D−4. We investigate the hypothesis of Ref. \cite{BBN} that the 2--loop QED initial state corrections to e+e− annihilation into a virtual neutral gauge boson, except power corrections of O((mf2/s)k),k≥1, can be represented in terms of these matrix elements and the massless 2-loop Wilson coefficients of the Drell-Yan process.
@article{arxiv.1107.4638,
title = {Two-loop QED Operator Matrix Elements with Massive External Fermion Lines},
author = {Johannes Blümlein and Abilio De Freitas and Wilhelmus van Neerven},
journal= {arXiv preprint arXiv:1107.4638},
year = {2011}
}