Towards Better Constraints on the Higgs Boson Mass: Two-Loop Fermionic   Corrections to sin^2(theta_eff)
  The complete two-loop electroweak fermionic corrections to the effective leptonic weak mixing angle, sin^2(theta_eff), are now available. Here we shortly present the methods applied and illustrate the implications on indirect prediction for the Higgs boson mass within the standard model. 
M.Awramik, M.Czakon, A.Freitas, G.Weiglein