QCD Green Functions and their Application to Hadron Physics
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| Format: | Artículo científico |
| Langue: | en |
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Sociedade Brasileira de Física
2007
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| _version_ | 1876444798640979968 |
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| author | Reinhard Alkofer |
| author_facet | Reinhard Alkofer |
| contents | QCD Green Functions and their Application to Hadron Physics Reinhard Alkofer Física, Astronomía y Matemáticas Nucleons Confinement Chiral Symmetry Breaking Infrared behaviour of Gluons and Quarks In a functional approach to QCD the infrared behaviour of Landau gauge Green functions is investigated. Itcan be proven that the ghost Dyson-Schwinger equation implies the Gribov-Zwanziger horizon condition. Itsrelation to the Kugo-Ojima confinement scenario is elucidated. Positivity violation for gluons is demonstrated,and the analytic structure of the gluon propagator is studied. Quark confinement is related to an infrared divergenceof the quark-gluon vertex. It is shown that in the latter various components are non-vanishing due to thedynamical breaking of chiral symmetry. As a result an infrared finite running coupling in the Yang-Mills sectoris derived whereas the running coupling related to the quark-gluon vertex is infrared divergent. In Coulombgauge QCD already the one-gluon-exchange (over-)confines. This leads to a vanishing quark propagator, andthus quarks are confined. Nevertheless colour singlet quantities derived from the quark propagator are welldefined.Especially the expression for the quark condensate proves that chiral symmetry is dynamically broken.As expected the properties of mesons can be directly calculated whereas the mass of coloured diquarks diverges,and thus diquarks are confined. The latter nevertheless possess a well-defined size. In the third part the resultsobtained so far will be used to formulate a covariant Faddeev approach to nucleons. The resulting amplitudesdescribe the quark core of the nucleon. Besides the mass of this state also the electromagnetic form factors arecalculated. The results for charge radii and magnetic moments as a function of the quark current mass providesome indication what the missing pion cloud may contribute to the nucleons properties. 2007 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46437203 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.1B Vol.37 |
| format | Artículo científico |
| id | redalyc_46437203 |
| institution | Redalyc |
| language | en |
| publishDate | 2007 |
| publisher | Sociedade Brasileira de Física |
| spellingShingle | QCD Green Functions and their Application to Hadron Physics Reinhard Alkofer Física, Astronomía y Matemáticas Nucleons Confinement Chiral Symmetry Breaking Infrared behaviour of Gluons and Quarks QCD Green Functions and their Application to Hadron Physics Reinhard Alkofer Física, Astronomía y Matemáticas Nucleons Confinement Chiral Symmetry Breaking Infrared behaviour of Gluons and Quarks In a functional approach to QCD the infrared behaviour of Landau gauge Green functions is investigated. Itcan be proven that the ghost Dyson-Schwinger equation implies the Gribov-Zwanziger horizon condition. Itsrelation to the Kugo-Ojima confinement scenario is elucidated. Positivity violation for gluons is demonstrated,and the analytic structure of the gluon propagator is studied. Quark confinement is related to an infrared divergenceof the quark-gluon vertex. It is shown that in the latter various components are non-vanishing due to thedynamical breaking of chiral symmetry. As a result an infrared finite running coupling in the Yang-Mills sectoris derived whereas the running coupling related to the quark-gluon vertex is infrared divergent. In Coulombgauge QCD already the one-gluon-exchange (over-)confines. This leads to a vanishing quark propagator, andthus quarks are confined. Nevertheless colour singlet quantities derived from the quark propagator are welldefined.Especially the expression for the quark condensate proves that chiral symmetry is dynamically broken.As expected the properties of mesons can be directly calculated whereas the mass of coloured diquarks diverges,and thus diquarks are confined. The latter nevertheless possess a well-defined size. In the third part the resultsobtained so far will be used to formulate a covariant Faddeev approach to nucleons. The resulting amplitudesdescribe the quark core of the nucleon. Besides the mass of this state also the electromagnetic form factors arecalculated. The results for charge radii and magnetic moments as a function of the quark current mass providesome indication what the missing pion cloud may contribute to the nucleons properties. 2007 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46437203 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.1B Vol.37 |
| title | QCD Green Functions and their Application to Hadron Physics |
| topic | Física, Astronomía y Matemáticas Nucleons Confinement Chiral Symmetry Breaking Infrared behaviour of Gluons and Quarks |
| url | https://www.redalyc.org/articulo.oa?id=46437203 |