A study of the XF and PT distributions in the production of D± charmed mesons

This work presents the first results of Fermilab Experiment 653, which was designed to study properties of particles containing charm or beauty produced by protons incident on emulsion. It describes in detail the apparatus of the experiment, which consisted of a hybrid emulsion spectrometer, and focuses on the Vertex Silicon Strip Detectors. Five million events were recorded on tape in the experiment's first run in 1985. A preliminary analysis yielded a D± peak with about 15 events above background, using only the electronic portion of the spectrometer and examining only the decay mode D± → K±π±πminus-plus with 60% of the first run data. Events were selected on the basis of a set of cuts requiring good separation of the primary and secondary vertices and the balance of the momentum of the decay particles. The pT2 and xF distributions of the D± candidates were examined; the pT2 (after Monte Carlo efficiency corrections) agrees with other experiments; the sF distributions seen is highly central with n in (1 - xF)n having a value much greater than 4. The occurrence of a leading particle effect is also examined and none is seen within the low statistics of the experiments