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oai:docta.ucm.es:20.500.14352/439822023-08-28T07:38:46Zcom_20.500.14352_14col_20.500.14352_15
Docta Complutense author Llanes Estrada, Felipe José author Alkofer, Reinhard author Fischer, Christian S author Schwenzer, Kai 2023-06-20T03:35:32Z 2023-06-20T03:35:32Z 2009-01 0003-4916 10.1016/j.aop.2008.07.001 https://hdl.handle.net/20.500.14352/43982 http://dx.doi.org/10.1016/j.aop.2008.07.001 http://arxiv.org/abs/0804.3042http://www.sciencedirect.com The infrared behavior of the quark–gluon vertex of quenched Landau gauge QCD is studied by analyzing its Dyson Schwinger equation. Building on previously obtained results for Green functions in the Yang–Mills sector, we analytically derive the existence of powerlawinfrared singularities for this vertex.Weestablish that dynamical chiral symmetry breaking leads to the self-consistent generation of components of the quark–gluon vertex forbidden when chiral symmetry is forced to stay in the Wigner–Weyl mode. In the latter case the running strong coupling assumes an infrared fixed point. If chiral symmetry is broken, eitherdynamically orexplicitly, the running coupling is infrared divergent. Based on a truncation for the quark–gluon vertex Dyson–Schwinger equation which respects the analytically determined infrared behavior, numerical results for the coupled system of the quark propagator and vertex Dyson–Schwinger equation are presented. The resulting quarkmass function aswell as the vertex function show only a very weak dependence on the current quark mass in the deep infrared. From this we infer by an analysis of the quark–quark scattering kernel a linearly rising quark potential with analmostmass independent string tensionin the case of brokenchiral symmetry. Enforcing chiral symmetry does lead to a Coulomb type potential. Therefore, we conclude that chiral symmetry breaking and confinement are closely related. Furthermore, we discuss aspects of confinement as the absence of long range van derWaals forces and Casimir scaling. An examination of experimental data for quarkonia provides further evidence for the viability of the presented mechanism for quark confinement in the Landau gauge. eng The quark-gluon vertex in Landau gauge QCD: Its role in dynamical chiral symmetry breaking and quark confinement journal article URL https://docta.ucm.es/bitstreams/d27c9547-fb53-4816-9ce1-e02d61dd70f0/download File MD5 e7317c1921fd796548bc4ee7a66b8ccb 1682579 application/pdf Llanes-Estrada_FJ22.pdf URL https://docta.ucm.es/bitstreams/5e752957-b770-42b5-93a9-437d581ddb4e/download File MD5 0e9a2a31f06964ba8f9303e9e1a6b0df 1294364 application/pdf Llanes-Estrada_FJ22preprint.pdf