[en] The Glashow-Salam-Weinberg model, that unifies the weak and electromagnetic forces of nature and gives a detailed description of the interactions between quarks and leptons is considered. The various experimental tests, either planned or that have been made, are described in detail and the interaction of quarks by the strong force and the theory of quantum chromodynamics are also discussed and theories proposing further unification of the forces of nature are outlined. (author)

[en] The current electroweak data and the constraints on the Higgs mass are discussed

[en] The most recent precision electroweak data from LEP, SLC and FNAL are reviewed. The mass of the Higgs boson is extracted from global electroweak fits and the influence of those measurements which are not very compatible with the Standard Model (SM) is discussed. Future expectations are also discussed

[en] Scientists at the Large Electron Positron collider (LEP) at CERN are now attempting to upgrade the machine built in the 1980s to study the W boson, and to search for the Higgs boson. This project, known as LEP2, is described in this article and aims to double LEP's energy at a cost of Pound 180 million. The many technical difficulties encountered are described, and the experimental aims and complexities of LEP2 are explained. (UK)

[en] The present status of precision electroweak data is reviewed. These data include measurements of e⁺e^-→f-barf, taken at the Z resonance at LEP, which are used to determine the mass and width of the Z-boson. In addition, measurements have also been made of the forward-backward asymmetries for leptons and heavy-quarks, and also the final state polarization of the τ-lepton. At SLAC, where the electron beam was polarized, measurements were made of the left-right polarized asymmetry, A_LR, and the left-right forward-backward asymmetries for b- and c-quarks. The mass, m_W, and width, Γ_W, of the W-boson have been measured at the Tevatron and at LEP, and the mass of the top-quark, m_t, has been measured at the Tevatron. These data, plus other electroweak data, are used in global electroweak fits in which various Standard Model (SM) parameters are determined. A comparison is made between the results of the direct measurements of m_W and m_t with the indirect results coming from electroweak radiative corrections. Using all precision electroweak data, fits are also made to determine limits on the mass of the Higgs boson, m_H. The influence on these limits of specific measurements, particularly those which are somewhat inconsistent with the SM, is explored. The data are also analysed in terms of the quasi-model-independent ε variables. Finally, the impact on the electroweak fits of the improvements in the determination of the W-boson and top-quark masses, expected from the Tevatron Run 2, is examined. (author)

[en] It was 20 years ago this month that particle physicists caught their first glimpse of the W boson. Now they have measured its mass so precisely that the Standard Model is facing an unprecedented challenge. (U.K.)