Protonium Spectroscopy and Identification of P-Wave and S-Wave Initial States of p Anti p Annihilations at Rest with the ASTERIX Experiment at LEAR

摘要

The ASTERIX experiment was designed with three main objectives: to study the general features of p anti p interactions at rest, to extend the work done so far in the spectroscopy of light mesons produced by p anti p annihilations at rest, and to search with high sensitivity for gluonium, baryonium structures, and N anti N states bound by strong interactions. The impact on the experimental program of the choice of a gaseous hydrogen target instead of a liquid one and of a large acceptance x-ray detector is discussed. Then the rate and signature of antiprotons stopping in the gas target is discussed, the x-ray detector is described, results from some initial tests and estimates of the performance of the apparatus expected for protonium spectroscopy are given, and initial states are identified. 21 refs., 21 figs. (ERA citation 11:007945)