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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

New method for determining the quark-gluon vertex

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Author(s):
Aguilar, A. C. [1] ; Binosi, D. [2, 3] ; Ibanez, D. [2, 3] ; Papavassiliou, J. [4, 5, 6]
Total Authors: 4
Affiliation:
[1] Univ Estadual Campinas, UNICAMP, Inst Phys Gleb Wataghin, BR-13083859 Sao Paulo - Brazil
[2] European Ctr Theoret Studies Nucl Phys & Related, I-38123 Villazzano, Trento - Italy
[3] Fdn Bruno Kessler, I-38123 Trento - Italy
[4] CSIC, E-46100 Valencia - Spain
[5] Univ Valencia, Dept Theoret Phys, E-46100 Burjassot - Spain
[6] Univ Valencia, IFIC, E-46100 Burjassot - Spain
Total Affiliations: 6
Document type: Journal article
Source: Physical Review D; v. 90, n. 6 SEP 23 2014.
Web of Science Citations: 47
Abstract

We present a novel nonperturbative approach for calculating the form factors of the quark-gluon vertex in terms of an unknown three-point function, in the Landau gauge. The key ingredient of this method is the exact all-order relation connecting the conventional quark-gluon vertex with the corresponding vertex of the background field method, which is Abelian-like. When this latter relation is combined with the standard gauge technique, supplemented by a crucial set of transverse Ward identities, it allows the approximate determination of the nonperturbative behavior of all 12 form factors comprising the quark-gluon vertex, for arbitrary values of the momenta. The actual implementation of this procedure is carried out in the Landau gauge, in order to make contact with the results of lattice simulations performed in this particular gauge. The most demanding technical aspect involves the approximate calculation of the components of the aforementioned (fully dressed) three-point function, using lattice data as input for the gluon propagators appearing in its diagrammatic expansion. The numerical evaluation of the relevant form factors in three special kinematical configurations (soft-gluon and quark symmetric limit, zero quark momentum) is carried out in detail, finding qualitative agreement with the available lattice data. Most notably, a concrete mechanism is proposed for explaining the puzzling divergence of one of these form factors observed in lattice simulations. (AU)

FAPESP's process: 12/15643-1 - Schwinger-Dyson equations: a tool for non-perturbative QCD
Grantee:Arlene Cristina Aguilar
Support type: Regular Research Grants