The optical trigger for beauty research, recent developments and perspectives

An optical detector sensitive to impact parameter has been tested in a particle beam. The device is based on the detection of Cerenkov light produced and trapped in a thin spherical crystal shell viewed by a fast photodetector. The detector is only sensitive to charged particles with a non‐zero impact parameter relative to the center of the crystal sphere. A prototype using a LiF 3 mm thick crystal has been tested and the experimental results are in agreement with the expectations. We discuss applications of this detector for fast selection of B‐events in fixed target experiments at proton accelerators. A program of technical development has started, aiming at a high efficiency in B‐meson pairs and a rejection factor of 100 against unwanted minimum bias events. We also present a modified collider configuration, the Asymmetric Tilted Collider, to optimize the sensitivity and the efficiency of a B‐meson experiment.