IR finiteness of the ghost dressing function from numerical resolution of the ghost SD equation
We solve numerically the Schwinger-Dyson ghost equation in the Landau gauge for a given, finite at k = 0 gluon propagator (i.e. the infrared exponent of its dressing function, αgluon, is 1) and under the usual assumption of constancy of the ghost-gluon vertex ; we show that there exist two possible...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2008 |
| País: | España |
| Institución: | Universidad de Huelva (UHU) |
| Repositorio: | Arias Montano. Repositorio Institucional de la Universidad de Huelva |
| Idioma: | inglés |
| OAI Identifier: | oai:ariasmontano.uhu.es:10272/18415 |
| Acceso en línea: | http://hdl.handle.net/10272/18415 |
| Access Level: | acceso abierto |
| Palabra clave: | Lattice Gauge Field Theories Lattice QCD QCD |
| Sumario: | We solve numerically the Schwinger-Dyson ghost equation in the Landau gauge for a given, finite at k = 0 gluon propagator (i.e. the infrared exponent of its dressing function, αgluon, is 1) and under the usual assumption of constancy of the ghost-gluon vertex ; we show that there exist two possible types of ghost dressing function solutions, as we have previously inferred from analytical considerations: one which is singular at zero momentum (the infrared exponent of its dressing function, αghost,† is < 0), satisfies the familiar relation αgluon + 2αghost = 0 and has therefore αghost = −1/2, and another one which is finite at the origin with αghost = 0 and violates the relation. It is most important that the type of solution which is realized depends on the value of the coupling constant. There are regular ones — αF = 0 — for any coupling below some value, while there is only one singular solution — αF < 0 —, obtained for a single critical value of the coupling. For all momenta k < 1.5GeV where they can be trusted, our lattice data exclude neatly the singular one, and agree very well with the regular solution we obtain at a coupling constant compatible with the bare lattice value. |
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