A trigger for beauty

Abstract

The possibility of B-meson experiments, in a fixed-target high-energy proton machine (Tevatron) is discussed. Compared to a B-meson factory experiment, it can produce 105 BB's per hour, using 108 protons per second, but it suffers from high background and needs high selectivity to cope with the million times higher interaction rate. To overcome these difficulties a technique called the “optical trigger for beauty” is proposed, based on the detection of Cherenkov photons produced in a 2 mm thick LiF crystal, through a fast photodetector. Its virtue is that it is opaque to minimum-bias events originating in a small target, but sensitive to the high impact parameter B-meson decay charged particles from a secondary vertex. Calculations and first simulations results give a good efficiency for B-meson detection. A multistep trigger, combining the “optical trigger” and a tracking detector, allows significant selection and a consequent enrichment of the data sample. Taking into account its fast response (∼ 1 ns), the above considerations can be extended to other hadronic machines, especially those with high-rate environments such as the LHC or SSC.