====== TTP12-021 The relation between the QED charge renormalized in MSbar and on-shell schemes at four loops, the QED on-shell beta-function at five loops and asymptotic contributions to the muon anomaly ====== In this paper we compute the four-loop corrections to the QED photon self-energy $\Pi(Q^2)$ in the two limits of $q = 0$ and $Q^2 \to \infty$. These results are used to explicitly construct the conversion relations between the QED charge renormalized in on-shell(OS) and $\MSbar$ scheme. Using these relations and results of Baikov et al. \cite{Baikov:2012zm} we construct the momentum dependent part of $\Pi(Q^2,m,\alpha)$ at large $Q^2$ at five loops in both $\MSbar$ and OS schemes. As a direct consequence we arrive at the full result for the QED $\beta$-function in the OS scheme at five loops. These results are applied, in turn, to analytically evaluate a class of asymptotic contributions to the muon anomaly at five and six loops. |**P. A. Baikov, K. G. Chetyrkin, J. H. Kühn and C. Sturm** | |** Nucl. Phys. B867 182-202\ 2013 25 pages, 6 figures; v2: final published version ** | | {{preprints:2012:ttp12-021.pdf|PDF}} {{preprints:2012:ttp12-021.ps|PostScript}} [[http://arxiv.org/abs/1207.2199|arXiv]] | | |