Simetria quiral: fótons, píons e núcleons

Detalhes bibliográficos
Autor(a) principal: Pupin, Joel César [UNESP]
Data de Publicação: 1994
Tipo de documento: Dissertação
Idioma: por
Título da fonte: Repositório Institucional da UNESP
Texto Completo: http://hdl.handle.net/11449/132669
http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/06-01-2016/000524316.pdf
Resumo: In this Work we study the role played by chiral and electromagnetic gauge symmetries, the weak constant 'g IND. A' and pion-nucleon couplings in three processes; single and double pion photo production and photon-nucleon interaction. The first two of them are treated at tree levei, whereas the last one includes one loop corrections. The role of the symmetries is analyzed considering the existence of relationships among various diagrams contributing to a given process. The influence of the way pions couple to nucleons is studied by comparing results obtained by means of the linear sigma model and the non linear model proposed by Weinberg. Finally, the role of 'g IND. A' is assessed by direct inspection of formal expressions. Our study showed that chiral symmetry is relevant only for double pion photo production. In particular, chiral symmetry does not influence the pion cloud contribution to the electromagnetic nucleon form factor, at least within the one loop approximation considered. These results pave the way for more comprehensive studies of the role of chiral symmetry in non perturbative approaches, such as the Skyrme model
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spelling Simetria quiral: fótons, píons e núcleonsPartículas (Física nuclear) - QuiralidadeFótonsPionsParticles (Nuclear physics) - ChiralityIn this Work we study the role played by chiral and electromagnetic gauge symmetries, the weak constant 'g IND. A' and pion-nucleon couplings in three processes; single and double pion photo production and photon-nucleon interaction. The first two of them are treated at tree levei, whereas the last one includes one loop corrections. The role of the symmetries is analyzed considering the existence of relationships among various diagrams contributing to a given process. The influence of the way pions couple to nucleons is studied by comparing results obtained by means of the linear sigma model and the non linear model proposed by Weinberg. Finally, the role of 'g IND. A' is assessed by direct inspection of formal expressions. Our study showed that chiral symmetry is relevant only for double pion photo production. In particular, chiral symmetry does not influence the pion cloud contribution to the electromagnetic nucleon form factor, at least within the one loop approximation considered. These results pave the way for more comprehensive studies of the role of chiral symmetry in non perturbative approaches, such as the Skyrme modelEste trabalho consiste no estudo do papel das simetrias quiral e de calibre eletromagnético, da constante 'g IND. A' e do tipo de acoplamento pion-núcleon em três processos: fotoprodução de um píon e de dois píons e interação fóton-núcleon. Os dois primeiros processos são tratados na aproximação em árvore, enquanto que no último são considerados também diagramas envolvendo um loop. O papel das simetrias é analisado investigando-se a existência de relações entre os vários diagramas de um dado processo. Já o papel do tipo de acoplamento pion-núcleon é analisado, comparando-se os resultados obtidos por meio de dois modelos de implementação da simetria quiral: o sigma linear e o não linear de Weinberg. Analogamente, o papel de 'g IND. A' é avaliado pela inspeção direta das expressões obtidas para os vários processos. Este estudo mostrou que, apenas no processo envolvendo dois píons externos a simetria quiral é relevante. Em particular, a simetria quiral é irrelevante para o fator de forma eletromagnético devido à nuvem piônica do núcleon, pelo menos no contexto das correções de um loop consideradas. Estes resultados constituem pontos de partida para o estudo mais abrangente do papel da simetria quiral em abordagens não perturbativas, tais como a do modelo de SkyrmeUniversidade Estadual Paulista (Unesp)Robilotta, Manoel Roberto [UNESP]Universidade Estadual Paulista (Unesp)Pupin, Joel César [UNESP]2016-01-13T13:27:34Z2016-01-13T13:27:34Z1994info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesis149 f. : ilapplication/pdfPUPIN, Joel César. Simetria quiral: fótons, píons e núcleons. 1994. 149 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Física Teórica, 1994.http://hdl.handle.net/11449/132669000524316http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/06-01-2016/000524316.pdf33015015001P7Alephreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPporinfo:eu-repo/semantics/openAccess2023-11-19T06:09:05Zoai:repositorio.unesp.br:11449/132669Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T18:06:36.251615Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false
dc.title.none.fl_str_mv Simetria quiral: fótons, píons e núcleons
title Simetria quiral: fótons, píons e núcleons
spellingShingle Simetria quiral: fótons, píons e núcleons
Pupin, Joel César [UNESP]
Partículas (Física nuclear) - Quiralidade
Fótons
Pions
Particles (Nuclear physics) - Chirality
title_short Simetria quiral: fótons, píons e núcleons
title_full Simetria quiral: fótons, píons e núcleons
title_fullStr Simetria quiral: fótons, píons e núcleons
title_full_unstemmed Simetria quiral: fótons, píons e núcleons
title_sort Simetria quiral: fótons, píons e núcleons
author Pupin, Joel César [UNESP]
author_facet Pupin, Joel César [UNESP]
author_role author
dc.contributor.none.fl_str_mv Robilotta, Manoel Roberto [UNESP]
Universidade Estadual Paulista (Unesp)
dc.contributor.author.fl_str_mv Pupin, Joel César [UNESP]
dc.subject.por.fl_str_mv Partículas (Física nuclear) - Quiralidade
Fótons
Pions
Particles (Nuclear physics) - Chirality
topic Partículas (Física nuclear) - Quiralidade
Fótons
Pions
Particles (Nuclear physics) - Chirality
description In this Work we study the role played by chiral and electromagnetic gauge symmetries, the weak constant 'g IND. A' and pion-nucleon couplings in three processes; single and double pion photo production and photon-nucleon interaction. The first two of them are treated at tree levei, whereas the last one includes one loop corrections. The role of the symmetries is analyzed considering the existence of relationships among various diagrams contributing to a given process. The influence of the way pions couple to nucleons is studied by comparing results obtained by means of the linear sigma model and the non linear model proposed by Weinberg. Finally, the role of 'g IND. A' is assessed by direct inspection of formal expressions. Our study showed that chiral symmetry is relevant only for double pion photo production. In particular, chiral symmetry does not influence the pion cloud contribution to the electromagnetic nucleon form factor, at least within the one loop approximation considered. These results pave the way for more comprehensive studies of the role of chiral symmetry in non perturbative approaches, such as the Skyrme model
publishDate 1994
dc.date.none.fl_str_mv 1994
2016-01-13T13:27:34Z
2016-01-13T13:27:34Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv PUPIN, Joel César. Simetria quiral: fótons, píons e núcleons. 1994. 149 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Física Teórica, 1994.
http://hdl.handle.net/11449/132669
000524316
http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/06-01-2016/000524316.pdf
33015015001P7
identifier_str_mv PUPIN, Joel César. Simetria quiral: fótons, píons e núcleons. 1994. 149 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Física Teórica, 1994.
000524316
33015015001P7
url http://hdl.handle.net/11449/132669
http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/06-01-2016/000524316.pdf
dc.language.iso.fl_str_mv por
language por
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 149 f. : il
application/pdf
dc.publisher.none.fl_str_mv Universidade Estadual Paulista (Unesp)
publisher.none.fl_str_mv Universidade Estadual Paulista (Unesp)
dc.source.none.fl_str_mv Aleph
reponame:Repositório Institucional da UNESP
instname:Universidade Estadual Paulista (UNESP)
instacron:UNESP
instname_str Universidade Estadual Paulista (UNESP)
instacron_str UNESP
institution UNESP
reponame_str Repositório Institucional da UNESP
collection Repositório Institucional da UNESP
repository.name.fl_str_mv Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)
repository.mail.fl_str_mv
_version_ 1808128896490536960

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