Higgs-Boson Mass Limits and Precise Measurements beyond the Standard Model

The triviality and vacuum stability bounds on the Higgs-boson mass ($\mh$) were revisited in presence of weakly-coupled new interactions parameterized in a model-independent way by effective operators of dimension 6. The constraints from precision tests of the Standard Model were taken into account. It was shown that for the scale of new physics in the region $\Lambda \simeq 2 \div 50 \tev$ the Standard Model triviality upper bound remains unmodified whereas it is natural to expect that the lower bound derived from the requirement of vacuum stability is substantially modified depending on the scale $\La$ and strength of coefficients of effective operators. A natural generalization of the standard triviality condition leads also to a substantial reduction of the allowed region in the ($\Lambda,\mh$) space.