{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25746"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25746","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The reaction p p -> p p pi+ pi- at 7.9 BeV/c","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.","abstract_html":"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.","abstract_has_math":false,"creators":["Grether, Donald Frank"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Sard, R.D."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-07-11T14:27:58Z","date_published":"2011-07-11T14:27:58Z","updated_at":"2026-07-22T22:25:26Z","subjects":["hydrogen bubble chamber","quasi-three body production","pion exchange model"],"languages":["en"],"rights":["1968 Donald Frank Grether"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["6079633"],"render_values":[{"text":"6079633","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25746","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Sard, R.D."]},{"key":"dc:creator","label":"Author","values":["Grether, Donald Frank"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-07-11T14:27:58Z","10000-01-01","1968"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["hydrogen bubble chamber","quasi-three body production","pion exchange model"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1968 Donald Frank Grether"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["6079633","http://hdl.handle.net/2142/25746"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["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.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-11T14:27:58Z No. of bitstreams: 1 1968_grether.pdf: 4134983 bytes, checksum: 1f787651ba4565b21851dfd80025a53e (MD5)","Made available in DSpace on 2011-07-11T14:27:58Z (GMT). No. of bitstreams: 1 1968_grether.pdf: 4134983 bytes, checksum: 1f787651ba4565b21851dfd80025a53e (MD5) Previous issue date: 1968","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-11T14:27:58Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:33:18-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["The reaction p p -> p p pi+ pi- at 7.9 BeV/c"]}]}],"canonical_facts":{"dc:contributor":["Sard, R.D."],"dc:creator":["Grether, Donald Frank"],"dc:date":["2011-07-11T14:27:58Z","10000-01-01","1968"],"dc:description":["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.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-07-11T14:27:58Z No. of bitstreams: 1 1968_grether.pdf: 4134983 bytes, checksum: 1f787651ba4565b21851dfd80025a53e (MD5)","Made available in DSpace on 2011-07-11T14:27:58Z (GMT). No. of bitstreams: 1 1968_grether.pdf: 4134983 bytes, checksum: 1f787651ba4565b21851dfd80025a53e (MD5) Previous issue date: 1968","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-07-11T14:27:58Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:33:18-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"],"dc:identifier":["6079633","http://hdl.handle.net/2142/25746"],"dc:language":["en"],"dc:rights":["1968 Donald Frank Grether"],"dc:subject":["hydrogen bubble chamber","quasi-three body production","pion exchange model"],"dc:title":["The reaction p p -> p p pi+ pi- at 7.9 BeV/c"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:26Z"}