264 research outputs found
Large Nc means Nc=3
We show that the nonperturbative solution of the SU(2) linear sigma model
field theory requires color number Nc=3. Also, we show that the three-point and
four-point functions bootstrap (or nonperturbatively ``shrink'') in the chiral
limit to the tree amplitudes. Independently, we show that a chiral phase
transition for Nf=2 requires Tc=180 MeV, consistent with the computer lattice
value (173 +/- 8 MeV).Comment: 9 pages, LaTeX. Invited talk given at the Large Nc Workshop, ASU,
January 200
Consistently computing the K -> pi long distance weak transition
First we extract the long-distance (LD) weak matrix element from certain data
and give compatible theoretical estimates. We also link this LD scale to the
single-quark-line (SQL) transition scale and then test the latter SQL scale
against the decuplet weak decay amplitude ratio. Finally, we study LD decay.
All of these experimental and theoretical values are in good agreement. We
deduce an average value from eleven experimental determinations compared to the
theoretical SQL values average.Comment: 19 pages, 9 figures minor change to the Conclusions and abstract
sectio
Circumventing the axial anomalies and the strong CP problem
Many meson processes are related to the U_A(1) axial anomaly, present in the
Feynman graphs where fermion loops connect axial vertices with vector vertices.
However, the coupling of pseudoscalar mesons to quarks does not have to be
formulated via axial vertices. The pseudoscalar coupling is also possible, and
this approach is especially natural on the level of the quark substructure of
hadrons. In this paper we point out the advantages of calculating these
processes using (instead of the anomalous graphs) the graphs where axial
vertices are replaced by pseudoscalar vertices. We elaborate especially the
case of the processes related to the Abelian axial anomaly of QED, but we
speculate that it seems possible that effects of the non-Abelian axial anomaly
of QCD can be accounted for in an analogous way.Comment: 13 pages, some typos corrected, published in Prof. D. Tadic's
memorial issue of Fizika B, expanded version of hep-ph/051212
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