Performance of the DELPHI detector

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1991

The measurement of the moments of hadronic mass spectrum and of lepton energy spectrum based on a sample of semileptonic decays of the b hadron selected from Z 0 → b b events recorded with the Delphi detector at LEP, are presented. These results are interpreted in terms of constraints on the quark masses and on the b-quark kinetic energy value.

A search for excited leptons with the DELPHI detector at LEP is reported. The data analysed correspond to an integrated luminosity of about 539 pb −1 collected at centre-of-mass energies ranging from 189 GeV to 208 GeV. The search for pairproduced excited leptons establishes 95% confidence level mass limits in the region between 95 GeV/c 2 and 103 GeV/c 2 , depending on the channel. The search for singly produced excited leptons establishes upper limits on the ratio of the coupling of the excited lepton to its mass (λ/m * ) as a function of the mass.

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995

The general purpose particle detector DELPHI at the Large Electron Positron collider at CERN was built to give the complete information of each event. DELPHI uses ring imaging Cherenkov counters to provide hadron identification in most of the momentum range below 40 GeV/c and over almost the full solid angle. Charged particles traversing gaseous and liquid fluorocarbon radiators create photons used for Cherenkov angle reconstruction. Some of the design features of the detector will be presented, with emphasis on the experience which was gained in the operation of these large systems. The hadron identification power of the ring imaging Cherenkov detector closely meets the main design values. Data processing and performance of the detector will be discussed using dimuon events collected during 1994. Pion rejection factors for kaon tagging will be shown.

IEEE Transactions on Nuclear Science, 1993

One quarter of the Forward Ring Imaging Cherenkov detector is installed and has been operated in the DELPHI experiment. The detector covers the forward-backward regions (15°<8@<35°). Two radiator systems are used for particle identification in the momentum range up to 40 GeV/c, a liquid Perfluorohexane and the Perfluorobutane gas. UV-photons with wave lenghts from ~170 nm to ~200 nm (7.3-6.2eV) are detected with high efficiency. The total active area of the photon detector is ~8m2.

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1995

The ring imaging Cherenkov detector in the DELPHI Experiment at LEP allows hadron identification over a momentum range up to about 40 Gev/c over a near to 4rr solid angle. Photons emitted by charged particles traversing gas and liquid radiators which are filled with UV-transparent perfluorocarbons, are used for Cherenkov angle reconstruction. Stable operation ensures that the detector is an efficient and powerful instrument. Monitoring of the detector parameters is of utmost importance to achieve good data quality and adequate data processing. The hadron identifying power of the ring imaging Cherenkov detector closely meets the main design values. Computerized control and monitoring features of the different subsystems will be presented. The interplay between detector parameters and the particle separating capacity of the detector will be discussed.