Actas de congresos
Dressed perturbation theory: Perturbative approach to Dyson-Schwinger and Bethe-Salpeter equations
Fecha
2014-02-12Registro en:
Proceedings of Science, v. 02-06-September-2013.
1824-8039
2-s2.0-84977107263
Autor
Universidade Estadual Paulista (UNESP)
Institución
Resumen
Dressed perturbation theory (DPT) is a perturbative approach based on the idea of using dressed propagators, instead of free propagators like in ordinary perturbation theory. Quark and gluon self-energies are added to the free part of the QCD action and subtracted from the interaction part. The added self-energies are determined self-consistently via a devised symmetry-preserving power counting scheme. Correlation functions are then calculated using the modified QCD interaction according to the devised power counting. At zeroth order, DPT is very similar to the rainbow-ladder truncation scheme for Dyson-Schwinger and Bethe-Salpeter equations; the first nontrivial perturbative contribution introduces vertex corrections. Dynamical chiral symmetry breaking is realized in the light-quark sector; Goldstone's theorem and the axial-vector Ward-Takahashi identity are satisfied in the chiral limit. Higher order contributions can be calculated in a systematic, symmetry-preserving and controllable way, like in ordinary perturbation theory.