Potential for B-physics measurements with a fixed-target proton-collision experiment

Sammanfattning: HERA-B is a high-energy physics experiment at HERA. It is a fixed-target experiment with a forward spectrometer to benefit from the strong boost of beauty hadrons. The main goal of HERA-B is to detect and measure the degree of CP violation in exclusive B-decays, with emphasis on the {em golden} decay, $golden$. A computer simulated study on this decay is presented and the accuracy of the measurement is estimated. Necessary conditions for a detection of CP violation are investigated. Various other channels are reviewed, which can give a sign of CP violation within and beyond the Standard Model. Very high rates are required for measurements of the typically very much suppressed signals. The thesis includes a comparison of the situation with the B-factories and the hadron colliders. HERA-B has a very tight time schedule %and the gained experience has an impact %on the future experiments at LHC. and physics measurements will be performed even before the detector is completed. In particular, the order of installation of detector parts is determined not only by technical factors but also by the feasibility to measure the $b$ cross-section, which is a crucial parameter in the precision of any $B$-physics measurements at HERA-B. A thorough study has been performed on the possibilities to measure the $b$ cross-section with a partially equipped detector. The emphasis is placed on the inclusive decay $B ightarrow J/psi X$. Studies on double semileptonic decays and $Upsilon$ decays are also presented.