3,179 research outputs found
Infrared exponents of Yang-Mills theory
In this talk I summarise recent results on the infrared exponents of
SU()-Yang-Mills theory. I discuss a self-consistent power law solution for
the Dyson-Schwinger equations for general 1PI-Greens functions in the infrared.
The corresponding running coupling has a fixed point at zero momentum, which
turns out to be universal and gauge invariant within a class of transverse
gauges. When calculated on a torus the infrared exponents of the ghost and
gluon propagators differ from the corresponding continuum solutions. They
agree, however, well with results from lattice calculations.Comment: 6 pages, 3 figures, talk presented at Lattice2005(Topology and
Confinement), Dublin, July 25-30, 2005. v2: reference adde
Bethe-Salpeter equations: mesons beyond the rainbow-ladder truncation
We investigate masses of light mesons from a coupled system of
Dyson--Schwinger (DSE) and Bethe--Salpeter equations (BSE), taking into account
dominant non-Abelian, sub-leading Abelian, and dominant pion cloud
contributions to the dressed quark-gluon vertex. The axial-vector
Ward-Takahashi identity preserving Bethe-Salpeter kernel is constructed and the
spectrum of light mesons calculated. Our model goes significantly beyond the
rainbow-ladder. We find that sub-leading Abelian corrections are further
dynamically suppressed, and that our results supersede early qualitative
predictions from simple truncation schemes.Comment: 4 pages, 3 figures, 1 table. Talk given at the 5-th Int. Conf. on
Quarks and Nuclear Physics, Beijing, September 21-26,200
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