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 10 5 B B 's per hour, using 10 8 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.