QCD spectral sum rules and spontaneously broken chiral symmetry

The gap Delta = 4 pi f(pi) similar or equal to 1.2 GeV of spontaneous chira l symmetry breaking is introduced as a scale delineating resonance and cont inuum regions in the QCD spectral sum rules for vector mesons. Basic curren t algebra results are easily recovered, and accurate sum rules for the lowe r moments of the spectral distributions are derived. The in-medium scaling of vector meson masses finds a straightforward interpretation, but only in the narrow width limit. (C) 2000 Elsevier Science B.V. All rights reserved.