Complete Two Loop Bosonic Contributions to the Muon Lifetime in the Standard Model

The last missing correction to the muon lifetime in the standard model at O(α²) coming from gauge and Higgs boson loops is presented. The associated contribution to the parameter Δr in the on-shell scheme ranges from 6×10^-5 to -4×10^-5 for Higgs boson masses from 100 GeV to 1 TeV. This result translates into a shift of the W boson mass which does not exceed ±1 MeV in the same range and amounts, in particular, to approximately -0.8 MeV for a 115 GeV Higgs boson.