Global Electroweak Fit and Its Implication for Z

Among the Z-pole observables, AFB(0,b) and Ae display moderately large standard deviations from the Standard Model predictions. This result can be interpreted as independent experimental evidence for new physics beyond the SM, even if the 125 GeV Higgs-like boson at the LHC is ultimately confirmed as the SM Higgs. A recalculated global electroweak fit with a model-independent Z' shows that Z' can simultaneously suppress AFB(0,b) and Ae at the Z-pole, and reduce the largest deviation from 2.6σ in SM to 1.0σ in our scenario. The Z' fitting results also support a negative S parameter.