How Strong is the Evidence for Electroweak Corrections Beyond the Running of $\alpha$?

Abstract

The evidence for electroweak radiative corrections not contained in $\alpha(m_Z)$ is examined. At low energies there is very strong evidence in the analysis of the unitarity of the CKM matrix. At LEP and collider experiments the current direct signals are not strong, but there is substantial indirect evidence, which will likely become sharper when $m_t$ is determined. The advantage of using $(\Delta r)_{res}$ as a measure of these effects is emphasized. In order to improve the direct evidence, more accurate measurements of $m_W$ and the on--resonance asymmetries are indicated.