On the Role of the Higgs Mechanism in Present Electroweak Precision Tests

Abstract

Based on the observables $\MW$, $\Gamma_l$, $\bar\sw^2(\MZ^2)$, we evaluate the parameters $\Delta x, \Delta y$ and $\varepsilon$ at one-loop level within an electroweak massive vector-boson theory, which does not employ the Higgs mechanism. The theoretical results are consistent with the experimental ones on $\Delta x$, $\Delta y$, $\varepsilon$. The theoretical prediction for $\Delta y$ coincides with the standard-model one (apart from numerically irrelevant terms which vanish for $\MH\to\infty$). Non-renormalizability only affects $\Delta x$ and $\varepsilon$, which differ from the standard-model results by the replacement $\log\MH\to\log\Lambda$ for a heavy Higgs mass, $\MH$ (where $\Lambda$ denotes an effective UV cut-off).