Consequences of Recent Electroweak Data and W-mass for the Top Quark and Higgs Masses

Abstract

We critically reexamine the precision tests of the standard model by coupling the current world average value of $M_W$ with the recent LEP electroweak data with the aid of a modified ZFITTER program to include the dominant two-loop and QCD-EW mixed terms. The results show a clear evidence of nonvanishing electroweak radiative corrections. The recent CDF $m_t$ is a solution of the minimal ${\chi }^2$-fits to the recent LEP data set and $M_W=80.23(18)$ GeV but with a heavy Higgs scalar, i.e., $m_t=179$ GeV and $m_H=300$ GeV. We discuss how sensitive $m_t$ and $m_H$ are depending on the exact value of $M_W$ even within the present uncertainty, as well as on ${\alpha }_s$ and $\alpha (M_Z)$. We show how the future improvements on $M_W$ can discriminate different values of $m_t$ and $m_H$ from the electroweak data and provide a crucial and decisive test for the standard model.

Comments: 6 pages, 2 postcript figures (appended), latex, Presented at Beyond the Standard Model IV, Granlibakken, Lake Tahoe, CA (December 13 -19, 1994)