The readout system of the HERA-B Inner Tracker and prospects of HERA-B in the field of Drell-Yan physics

Abstract

The HERA-B experiment at the HERA accelerator at DESY is designed and built to measure CP violation in the system of neutral B mesons. One sub-detector is the Inner Tracker, which is built of Micro-Strip Gas Chambers with Gas Electron Multiplier (GEM-MSGC) with about 120,000 readout channels. Using results of test beam experiments, the readout system of the Inner Tracker was finalised in its design. At HERA-B, it was extended from small test installations to the full system during the installation 1999/2000. The software needed for the processing of the raw data was developed. This thesis describes the readout hardware and software in use at HERA-B and the steps needed for commissioning. Results from the first year of running at HERA-B are reported. In a second part of this thesis, the prospects of HERA-B to contribute to the field of Drell-Yan physics are evaluated, where significant deviations from the predictions of perturbative QCD were observed. Starting from an analysis of the di-muon triggered data of the run period 2000, the expected number of high-mass muon pairs produced by the Drell-Yan process is extrapolated. With a conservative estimate of the outcome of the detector and trigger improvements, about 26,000 high-mass Drell-Yan pairs are expected for the run period 2002. Although the measurement will be difficult due to the low number of events at higher transverse momentum, this will allow a first measurement of the angular distributions of Drell-Yan pairs produced in pN collisions.