Electroweak Data and the Higgs Boson Mass: A Case for New Physics

Abstract

Because of two 3 sigma anomalies, the Standard Model (SM) fit of the precision electroweak data has a poor confidence level, CL= 0.010. Since both anomalies involve challenging systematic issues, it might appear that the SM could still be valid if the anomalies resulted from underestimated systematic error. Indeed the CL of the global fit could then increase to 0.65, but that fit predicts a small Higgs boson mass, m_H=43 GeV, that is only consistent at CL=0.035 with the lower limit, m_H > 114 GeV, established by direct searches. The data then favor new physics whether the anomalous measurements are excluded from the fit or not, and the Higgs boson mass cannot be predicted until the new physics is understood. Some measure of statistical fluctuation would be needed to maintain the validity of the SM, which is unlikely by broad statistical measures. New physics is favored, but the SM is not definitively excluded.