Quark and lepton couplings in the weak interactions

We present a comprehensive study of the weak neutral-current interactions of u and d quarks and of the electron. A model-independent analysis using data from deep-inelastic, inclusive-pion, elastic, and exclusive-pion neutrino processes provides a unique determination of the u- and d-quark couplings. For electron couplings, neutrino-electron-scattering, atomic-parity-violation, and new polarized-electron-scattering data are discussed. With the assumption of a single Z⁰ boson, we show that the electron couplings are almost uniquely determined. The predictions of the Weinberg-Salam model (for sin²θW=0.20-0.30) are in remarkably good agreement with our results.