Contact persons: D. Bertrand, C. De Clercq
Members of the group:  D. Bertrand, C. De Clercq,J.-P. De Wulf, J. D'Hondt, B. Goorens, J. Lemonne, W. Van Doninck, C. Vander Velde, L. Van Lancker, J. Wickens

The DELPHI experiment:
DELPHI is a detector for e⁺e^- physics, with special emphasis on powerful particle identification , three-dimensional information, high granularity and precise vertex determination. It was installed at LEP (Large Electron and Positron collider) at CERN where it has operated between August 1989 and November 2000.

The official DELPHI homepage contains information on the detector, the physics goals and  event pictures. 

Activities at the IIHE:

• The Belgian laboratories (IIHE(ULB-VUB), UA,  UMH) have designed, constructed and maintained the 700 Forward Muon Chambers (MUF) of the DELPHI detector. This consisted of the construction of the detector itself, the development of the readout and trigger hardware and software and the development of the offline software for simulation and data reconstruction. There are Photographs of the MUF detector construction, transport and installation in Brussels and in DELPHI.
  

• Some engineers in Brussels have taken responsibilities in the Central Trigger of the DELPHI experiment.

• The DELPHI  raw data reconstruction software DELANA, and the event viewing software were partly designed and maintained by physicists of the IIHE.

• The IIHE was also involved in the maintenance of the Surround Muon Chambers (MUS) software.

• The Brussels group is presently performing analyses of the e⁺e^- -> W⁺W^- data with the aim of:

• W mass measurement and study of colour reconnection in the fully hadronic channel (J. D'Hondt)

• Spin Density Matrix analysis and measurement of CP-violating anomalous Triple Gauge boson Couplings (C. De Clercq, J. Lemonne).

• In the past our group was involved in :
• analysis of di-muon final states around and below the Z⁰ peak (Cao Fang,  Catherine De Clercq, Jacques Lemonne, Frederic Stichelbaut)
  
• analysis of di-tau  final states around the Z⁰ peak (Daniel Bertrand, Veronique Lefébure)
• measurement of charged Triple Gauge boson Couplings in the fully hadronic WW channel (A. Van Lysebetten)

• Frederic Stichelbaut, ULB, 1993, "La Detection des Muons dans l'Experience DELPHI et son Role dans l'Etude de l'Interaction e+e- -> mu+mu-"
  
• Cao Fang, VUB, 1994, "A study of the Z0 lineshape at LEP through the reaction e+e- -> mu+mu-"
• Veronique Lefebure, ULB, 1997, "A measurement of the tau polarisation in e+e- interactions produced at LEP"
• Ann Van Lysebetten, VUB, 2001, "Contribution to the study of the Triple Gauge Boson Couplings in fully hadronic WW final states at LEP2"
  
• Jorgen D'Hondt, VUB, 2003, "Measurements of the W boson resonance at LEP2" - text