Study of hadron-hadron collisions at high E/sub T/ and/or high mass di-muon production in open geometry at 800 GeV/c

During the last year this experiment had its first run with 800 GeV/c protons from TeV II. A total of 700 hours of beam time was delivered; the authors took 380 hours for set up and calibrations and 320 hours were used for data taking. The upgraded multi-particle-spectrometer (MPS) has several improvements and additions. A large number of triggers were obtained for various targets with high E/sub T/ and interacting beam (IB) triggers and for dimuon studies. A preliminary look at the jet data during the run showed that at 800 GeV/c the trigger was working well. This was deduced from the study of the E/sub t/ dependence of the trigger rate for Global and reduced global triggers. The on-line planarity studies showed the expected variation with E/sub t/. The sum of all the signals from the large angle, the insert, the forward and the beam calorimeters showed a clean peak at the total energy of 800 GeV with a width of about 10 percent. The total luminosity obtained for high E/sub t/ and jet studies was about 30 nb-1 as compared to 5 nb-1 for the 1981 run. The dimuon sector of the experiment has been analyzed by the Indiana group. They were able to reconstruct di-muon masses from 2 to 5 GeV. A clear psi/J peak was observed in μ+μ- events from events produced with H, C, and Cu targets, albeit with small statistics. No such psi/sub J/ signal was observed for the μ-μ- and μ+μ+ combinations. The mass distributions were fitted with a formula