Comprehensive analysis of data pertaining to the weak neutral current and the intermediate-vector-boson masses

Abstract

The results of a comprehensive analysis of existing data on the weak neutral current and the W and Z masses are presented. The principal results are the following. (a) There is no evidence for any deviation from the standard model. (b) A global fit to all data yields ${\sin }^2$ ${\mathrm{\theta }}_{\mathrm{W}}$≡1-${\mathrm{M}}_{\mathrm{W}}$ ${\mathrm{}}^2$/${\mathrm{M}}_{\mathrm{Z}}$ ${\mathrm{}}^2$=0.230±0.0048, where this error and all others given here include full statistical, systematic, and theoretical uncertainties (computed assuming three fermion families, $m_t$≤100 GeV, and $M_H$≤1 TeV). (c) Allowing ρ≡$M_W$ ${\mathrm{}}^2$/($M_Z$ ${}^2$ ${\cos }^2$ ${\mathrm{\theta }}_{\mathrm{W}}$) as well as ${\sin }^2$ ${\mathrm{\theta }}_{\mathrm{W}}$ to vary one obtains ${\sin }^2$ ${\mathrm{\theta }}_{\mathrm{W}}$=0.229±0.0064 and ρ=0.998±0.0086. This implies 90%-confidence-level (C.L.) upper limits of 0.047 and 0.081 for the vacuum expectation values (relative to those of Higgs doublets) for Higgs triplets with weak hypercharge of 0 and ±1, respectively. (d) The parameter ${\delta }_W$≡Δr-Δ$s^2$(1-Δr)/${\sin }^2$ ${\mathrm{\theta }}^0$, which is a measure of the radiative corrections relating deep-inelastic neutrino scattering, the W and Z masses, and muon decay, is determined to be 0.112±0.037. This is consistent with the value ${\delta }_W$=0.106 expected for $m_t$=45 GeV and $M_H$=100 GeV and establishes the existence of radiative corrections at the 3σ level. (e) The radiative corrections are sensitive to isospin breaking associated with a large $m_t$.