Chiral symmetry, the angular content of the vector current in QED and QCD, and the holographic description of hadrons - High Energy Physics - PhenomenologyReportar como inadecuado




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Abstract: We perform a general chiral symmetry and unitarity based analysis of a localprocess of the fermion-antifermion creation from the vacuum by a high-energyphoton as well as an explicit partial wave analysis of the vector current inQED and QCD. It turns out that such a local process proceeds necessarily via acertain superposition of the $S$- and $D$-wave contributions. These constraintsfrom chiral symmetry and unitarity are confronted then with the well-knowntheoretical and experimental results on $e^+e^-\to\gamma\to e^+e^-$,$e^+e^-\to\gamma\to \mu^+\mu^-$, and $e^+e^-\to\gamma\to q\bar{q}$ in theultrarelativistic limit. It is shown that these well-known results areconsistent with the $S+D$-wave structure of the vertex and are inconsistentwith the pure $S$-wave interpretation of the vertex. Then a free quark loop inthe $1^{-}$ channel, representing the leading term in the Operator ProductExpansion, contains both $S$-wave and $D$-wave contributions. This fact rulesout the possibility that there is only one radial trajectory for the$ ho$-mesons with the fixed $S$-wave content. It also implies that allholographic models that assume a pure $S$-wave content of the $ ho$-meson haveto fail to satisfy the matching conditions at the ultraviolet border $z=0$.



Autor: L. Ya. Glozman, A. V. Nefediev

Fuente: https://arxiv.org/



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