1,401 research outputs found
Ratios of periods for tensor product motives
In this article we prove some period relations for the ratio of Deligne's
periods for certain tensor product motives. These period relations give a
motivic interpretation for certain algebraicity results for ratios of
successive critical values for Rankin-Selberg L-functions for proved by G\"unter Harder and the second author.Comment: In this revised version, we have made some minor modifications
according to the comments by the refere
Confinement, DCSB, Bound States, and the Quark-Gluon Vertex
Aspects of the dressed-quark-gluon vertex and their role in the gap and
Bethe-Salpeter equations are briefly surveyed using an intuitive model. The
model allows one to elucidate why a linear extrapolation to the chiral limit of
extant lattice data on the dressed-quark mass-function overestimates this
function and hence the value of the vacuum quark condensate. The diagrammatic
content of the vertex described is explicitly enumerable. This property is
essential to the symmetry preserving study of bound state properties. It
facilitates a realistic analysis of vector and pseudoscalar meson masses, and
also allows the accuracy of standard truncations to be gauged. The splitting
between vector and pseudoscalar meson masses is observed to vanish as the
current-quark mass increases. That argues for the mass of the pseudoscalar
partner of the Upsilon(1S) to be above 9.4GeV. Moreover, in this limit the
rainbow-ladder truncation provides an increasingly accurate estimate of a bound
state's mass.Comment: 6 pages, Contribution to the Proceedings of "QCD Down Under", Special
Centre for the Subatomic Structure of Matter, University of Adelaide,
10-19/March/200
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