IV.P122 — Muon mass exponent

The muon-to-electron mass ratio is m_mu/m_e = iota_tau^(-5)(1 + delta_mu) where delta_mu ~ -0.04 is an O(alpha) radiative correction; the bare topological exponent is 5, and the corrected prediction m_e iota_tau^(-4.96) ~ 106.1 MeV matches experiment (105.66 MeV) to 0.4%.