EXPERIMENTAL STUDY OF ANTIPROTON-PROTON COLLISIONS AT 50 GEV/C USING THE FERMILAB 30-INCH BUBBLE CHAMBER-PROPORTIONAL WIRE CHAMBER HYBRID SYSTEM
Abstract
The charged multiplicity cross sections of 50 GeV/c pp annihilation reactions are examined through the use of the corresponding pp - pp cross section differences. In addition, various four-constraint reactions such as the elastic reaction and the reaction pp (--->) pp (pi)('+)(pi)('-) are studied at the same incident p beam momentum. The source of the data is a film sample of 92,000 pictures of the 30-inch hydrogen bubble chamber exposed to a p enriched 50 GeV/c negative beam. There are 2.8 antiprotons per picture on the average. The proportional wire chambers allow for precise measurement of beam and fast secondary charged particle trajectories. The average charged multiplicity of the difference distribution is larger than that of the pp sample as a whole. Although the pp - pp total cross section difference is (TURN) 12%, about 50% of the pp events with 14 charged particles appear in the difference. The difference distribution is in good agreement with a model by Eylon and Harari for pp annihilations. The model is based on simple counting rules for quark interaction diagrams. The form of the difference distribution has an energy dependence which may be interpreted as evidence for multiple cluster formation for pp annihilations above about 30 GeV. Alternatively, Koba-Nielsen-Olesen scaling describes the distribution over the entire range of existing data. Copius (DELTA) (1232) production and diffractive dissociation are exhibited in the reaction pp (--->) pp(pi)('+)(pi)('-). The subchannel reaction pp (--->) (DELTA)('-) ('-)(DELTA)('++(' )) is examined in terms of pion exchange. The cross sections for the reaction pp (--->) pp2(pi)('+)2(pi)('-) is determined. No statistically significant amount of annihilation is found into two, four, and six charged pions without associated neutral particles.
Degree
Ph.D.
Subject Area
Particle physics
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