15 papers
The three loop on-shell renormalization of QCD and QED
Kirill Melnikov, Timo van Ritbergen
We describe a calculation of the on-shell renormalization factors in QCD and QED at the three loop level. Explicit results for the fermion mass renormalization factor Zm and the on…
The three loop relation between the \bar {MS} and the pole quark masses
Kirill Melnikov, Timo van Ritbergen
The analytic relation between the \bar {MS} and the pole quark masses is computed to O(α_s^3) in QCD. Using this exact result, the accuracy of the large β_0 approximation is critic…
The three loop slope of the Dirac form factor and the 1S Lamb shift in hydrogen
Kirill Melnikov, Timo van Ritbergen
The last unknown contribution to hydrogen energy levels at order m alpha ^7, due to the slope of the Dirac form factor at three loops, is evaluated in a closed analytical form. The…
On the Precise Determination of the Fermi Coupling Constant from the Muon Lifetime
Timo van Ritbergen, Robin G. Stuart
The determination of the Fermi coupling constant, G_F, is examined in the light of recently calculated 2-loop QED corrections and planned experiments to measure the muon lifetime t…
The second order QCD contribution to the semileptonic b -> u decay rate
T. van Ritbergen
The order alpha_s^2 contribution to the inclusive semileptonic decay width of a b quark Γ(b -> X_u e \barν_e) is calculated analytically for zero mass u quarks.
Complete 2-loop Quantum Electrodynamic Contributions to the Muon Lifetime in the Fermi Model
Timo van Ritbergen, Robin G. Stuart
The complete 2-loop quantum electrodynamic corrections to the muon lifetime are calculated in the Fermi theory. The exact result for the effects of virtual and real photons, virtua…