Spectroscopy at Lear with an Internal Gas Jet Target PS202 Collaboration

Abstract

At LEAR Experiment PS202 will study exotic states such as glueballs (gg) and hybrids (gq\(\bar q\)) in \(\bar p\)p annihilation. This will be done using an internal H2 gas jet target. The set-up features high luminosity, 1031 cm−2 s−1, a compact and large acceptance detector and a fast and flexible trigger. Furthermore we will have precise tracking (silicon strip detectors and straw chambers), full π/K/p identification (correlating data from the tracker and the RICH identifier) and a powerful electromagnetic calorimeter. This set-up, having excellent signal detection efficiency and background rejection efficiency, will allow us to study a variety of rare processes. Our sensitivity will be 480 nb−1/day at L = 1031 cm−2 s−1. The first processes to be studied are p\(\bar p\) → φφ → K+K−K+K− and \(\bar p\)p → \(\bar K_S^OK_S^O\) →π+π−π+π−. Resonances are detected by monitor¬ing the reaction rates as a function of the LEAR beam momentum in 0.6 <P\(\bar p\) < 2.0 GeV/c. Later, reactions such as \(\bar p\)p → φω, φη, ηη, φφπ°, 4K (close to threshold) and φφ (tagging on φ′s) will be explored. Also the future programme will include studies of \(\bar p\)p collisions with a polarized jet target.