Accelerator physics at LEP

W Physics at LEP

A summary of the W-boson properties measured by the four LEP collaborations is presented here. These properties are updated to take into account the most recent results presented at the ICHEP98 Conference. 1 WW cross sections and W branching fractions After the period of running at the Z, the centre-of-mass energy of LEP has been progressively increased from 161 GeV, i.e., just above the W pair...

Precision Physics at LEP

W physics at LEP

Studying the properties of the W boson plays a key role in precision tests of the Standard Model. The key measurements performed over the last decade will be reviewed. W-pair and single-W cross-sections and W decay branching fractions are determined and agree well with theoretical predictions. Including the analysis of differential distributions, trilinear and quartic couplings of the W boson t...

Two Photon Physics at Lep

Figure 1. γγ collision in ee scattering These two photons then can interact to form a state X with mass Wγγ . The fourmomentum transfer qi to the photons depends on the angle and energy of the scattered electrons. When neither of the scattered electrons is detected (untagged events), the virtual photons are referred to as nearly real i.e. q 1 ≈ q 2 ≈ 0. This class of events allows several tests...

Precision Electroweak Physics at Lep

Progress in precisionmeasurements of electroweak observables at LEP continues steadily. The highlights of 1993 are: a new scan of the Z line shape with precise beam energy determination by resonant depolarization, leading to a measurement of the Z width with 1:5 10 3 precision; rst results on absolute cross sections with high-precision luminosity monitors; high e ciency b-tagging with microvert...