The quark-gluon vertex and the QCD infrared dynamics

Autor: Tobias Frederico, Wayne de Paula, Orlando Oliveira, J. P. B. C. de Melo
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: European Physical Journal C: Particles and Fields, Vol 79, Iss 2, Pp 1-33 (2019)
European Physical Journal
ISSN: 1434-6052
1434-6044
DOI: 10.1140/epjc/s10052-019-6617-7
Popis: The Dyson-Schwinger quark equation is solved for the quark-gluon vertex using the most recent lattice data available in the Landau gauge for the quark, gluon and ghost propagators, the full set of longitudinal tensor structures in the Ball-Chiu vertex, taking into account a recently derived normalisation for a quark-ghost kernel form factors and the gluon contribution for the tree level quark-gluon vertex identified on a recent study of the lattice soft gluon limit. A solution for the inverse problem is computed after the Tikhonov linear regularisation of the integral equation, that implies solving a modified Dyson-Schwinger equation. We get longitudinal form factors that are strongly enhanced at the infrared region, deviate significantly from the tree level results for quark and gluon momentum below 2 GeV and at higher momentum approach their perturbative values. The computed quark-gluon vertex favours kinematical configurations where the quark momentum $p$ and the gluon momentum $q$ are small and parallel. Further, the quark-gluon vertex is dominated by the form factors associated to the tree level vertex $\gamma_\mu$ and to the operator $2 \, p_\mu + q_\mu$. The higher rank tensor structures provide small contributions to the vertex.
Comment: Some rewriting. Version accepted for publication in Eur Phys J C
Databáze: OpenAIRE
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