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Title:The reaction p p -> p p pi+ pi- at 7.9 BeV/c
Author(s):Grether, Donald Frank
Doctoral Committee Chair(s):Sard, R.D.
Department / Program:Physics
Subject(s):hydrogen bubble chamber
quasi-three body production
pion exchange model
Abstract:The reaction p p -> p p pi+ pi- has been studied at an incident momentum of 7.9 BeV/c using the Brookhaven 80 inch hydrogen bubble chamber. App'roximate1y 3600 events of the 'reaction were identified; the cross section was determined to be 2.54 +/- .13 mb. The reaction is found to be dominated by production of the quasi-three body final state N*++ p pi-. A simple one pion exchange model is compared to the data and is shown to give gene'ra11y good results for invariant mass distributions for the entire final state, and for mass and angular distributions for the quasi-three body state. Discrepancies between the data and the model are found to be primarily associated with enhancements in the N*++ pi- of p pi+pi- mass distributions at about 1425 MeV and 1'700 MeV. Examination of the 1425 MeV enhancement indicates an apparent interference process rather than an incoherent sum of one pion exchange background and resonance production; the enhancement could not be identified as the N*(1470), the P11 wave resonance of pi-p phase shift analysis. Examination of the pi+ pi- mass distribution gives some indication for production of the p meson, but no indication of other pi+ pi- resonances. No evidence is found for resonances with Baryon number = 2.
Issue Date:1968
Genre:Dissertation / Thesis
Rights Information:1968 Donald Frank Grether
Date Available in IDEALS:2011-07-11
Identifier in Online Catalog:6079633

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