Leptonic and hadronic decays of the W/sup +-/ and Z bosons

The author makes a study of the decays W → eν and Z → e/sup +/e/sup -/, using the UA2 detector at the CERN pp-bar Collider. Measurements of the Standard Model parameters from samples of 257 W decay and 39 Z decay candidates are compared with expectations of the Standard Electroweak Model. The invariant mass distribution of jet-pairs observed in the UA2 central calorimeter is inspected with the aim to search for an excess of events in the region of the W and Z bosons, which would reveal their decays into quark-antiquark pairs. This study gives a detailed account of the methods of analysis used to keep the mass resolution below ≅ +- 10%. A structure is observed at the level of ≅ 2-3 standard deviations. Its shape, position and magnitude are consistent with Standard Model predictions