Particle physics phenomenology at high energy colliders

• Research unit: EU RFP
• Project number: 99.0043

Key words (English)

Precision electroweak physics; higgs physics; top physics; supersymmetry; alternative new physics scenarios;
Education; Training; Scientific Research; Social Aspects

Alternative project number (English)

EU project number: HPRN-2000-00149

Research programs (English)

EU-programme: 5. Frame Research Programme - 4.1.1 Research training networks

Short description (English)

See abstract

Further information (English)

Full name of research-institution/enterprise:
Paul Scherrer Institut PSI
Research Department Particles and Matter
Laboratory for Particle Physics

Partners and International Organizations (English)

Coordinator: Universität Granada (E)

Abstract (English)

The Monte Carlo generators RacoonWW and WPHACT for W-pair production and 4-fermion production are used for the analysis of LEP data. These generators were further improved and exploited. Anomalous triple gauge-boson couplings were implemented in RacoonWW and the theoretical uncertainty of the angular distribution of the produced W bosons was investigated. This is important for the measurement of the anomalous couplings at LEP. Furthermore, with WPHACT 2.0 a fully massive generator for 4-fermion production was developed.
At high energies, which will be realized for example at the Large Hadron Collider (LHC) or a future linear electron-positron collider, the emission of collinear or soft gauge bosons yields large radiative corrections that grow logarithmically with energy. We have evaluated these corrections for specific gauge-boson pair-production processes at the LHC and found sizeable effects. We have extended these investigations by studying these enhanced corrections at higher orders.
At the electron-proton collider HERA an excess of events with isolated high-energy leptons has been seen by the H1 experiment. In order to quantify precisely the SM contribution to these events, the QCD corrections to W production in electron-proton collisions have been calculated. These corrections are of the order of 10% and thus cannot explain the observed excess, but increase its significance owing to the reduction of the theoretical uncertainty.
One of the main tasks of the LHC is the search for the Higgs boson, the only missing particle of the Standard Model. In order to obtain precise predictions for the corresponding production cross sections higher-order corrections due to the strong interaction are essential. In the past year the calculation of these corrections for Higgs radiation off top quarks has been finished and the details will soon be published.

References in databases (English)

Swiss Database: Euro-DB of the
State Secretariat for Education and Research
Hallwylstrasse 4
CH-3003 Berne, Switzerland
Tel. [phone]
Swiss Project-Number: 99.0043