First Evidence for Electroweak Radiative Corrections from the New Precision Data

The analysis of the newest data on the leptonic $Z$-decays and $m_W$ appears to reveal the first manifestations of electroweak radiative corrections. In fact, these data differ, at the level of $2\sigma$, from their electroweak Born values, while they agree, to within $1\sigma$, with the theoretical values which take the electroweak radiative corrections into account. Previous data were within $1\sigma$ in agreement with both sets of values.