STATUS OF THE STANDARD MODEL a

. Subsequently, neutrino-nucleon and neutrino-electronscattering experiments improved to the per cent level, testing the weak interac-tion quantitatively. Electron-deuteron and electron-positron scattering, as wellas atomic parity violation experiments, are sensitive to weak-electromagneticinterference effects, and were crucial for the confirmation of the electroweakStandard Model (SM). The W and Z bosons were finally discovered directly bythe UA1