The reaction p p -> p p pi+ pi- at 7.9 BeV/c

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.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Grether, Donald Frank

Contributors dc:contributor

• Sard, R.D.

• hydrogen bubble chamber
• quasi-three body production
• pion exchange model

Statement dc:rights

• 1968 Donald Frank Grether

Language dc:language

en

Identifier

6079633

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25746