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V. Electroweak Precision Observables. What radiative corrections can teach us Basic formalism. g. g. Weak Decays: G F encodes information on the spectrum via radiative corrections. Muon Decay. D r m depends on parameters of particles inside loops. g. g.
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V. Electroweak Precision Observables • What radiative corrections can teach us • Basic formalism
g g Weak Decays: GFencodes information on the spectrum via radiative corrections Muon Decay Drm depends on parameters of particles inside loops
g g Comparingradiative corrections in different processes canprobeparticle spectrum Drm differs fromDrZ
Comparingradiative corrections in different processes canprobeparticle spectrum
Charged Current Interactions I G.B. Propagator Fermion Propagator Vertex Correction Box (finite)
Muon decay at one loop: Muon lifetime: Vertex, box, fermion prop Fermi constant & r : Tree level Charged Current Interactions II
Complication: Z mixing Neutral Current Interactions I G.B. Propagator Fermion Propagator Vertex Correction Box (finite)
Normalize to G: Remove r Vertex & ext leg Neutral Current Interactions II Neutral current l+f --> l+f at one loop: Normalization: Vector & axial vector couplings: Weak mixing:
The parameter: Weak mixing: Can impose constraints from global fits to EWPO via S,T,U-dependence of these quantities Oblique Parameters I G.B. Propagators
Oblique Parameters II Fit to electroweak precision observables: G.B. Propagators mH = 114.4 GeV Plus low-energy observables: atomic PV, PV electron scattering, scattering…