Bethe-Salpeter equations: mesons beyond the rainbow-ladder truncation

摘要

We investigate masses of light mesons from a coupled system ofDyson--Schwinger (DSE) and Bethe--Salpeter equations (BSE), taking into accountdominant non-Abelian, sub-leading Abelian, and dominant pion cloudcontributions to the dressed quark-gluon vertex. The axial-vectorWard-Takahashi identity preserving Bethe-Salpeter kernel is constructed and thespectrum of light mesons calculated. Our model goes significantly beyond therainbow-ladder. We find that sub-leading Abelian corrections are furtherdynamically suppressed, and that our results supersede early qualitativepredictions from simple truncation schemes.