Dresden 2000 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 14: Postersitzung / Theorie

HK 14.13: Poster

Donnerstag, 23. März 2000, 10:15–12:45, B 113

QCD SPECTRAL SUM RULES AND SPONTANEOUSLY BROKEN CHIRAL SYMMETRY — •Eugenio Marco and Wolfram Weise — Physik-Department,
Technische Universität München,
D-85747 Garching, Germany

The gap Δ = 4 π f_π ≃ 1.2 GeV of spontaneous chiral symmetry breaking is introduced as a scale delineating resonance and continuum regions in the QCD spectral sum rules for vector mesons. Moment sum rules are derived in which condensates with different dimension do not mix. We show that these QCD spectral sum rules combined with vector meson dominance for the resonant part plus the continuum starting at Δ imply well known current algebra relations. We also use realistic models for the spectral distributions of ρ and ω and show that the scale introduced by the chiral gap Δ still controls the transition from the resonance to the asymptotic QCD domain of the spectrum. The in-medium scaling of vector meson masses finds a straightforward interpretation, at least in the narrow width limit.