München 2006 – wissenschaftliches Programm

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HK: Physik der Hadronen und Kerne

HK 56: Elektromagnetische und Hadronische Sonden

HK 56.2: Vortrag

Freitag, 24. März 2006, 14:30–14:45, F

Fate of vector meson dominance or fate of QCD sum rules in a nuclear medium — •Stefan Leupold — Institut für Theoretische Physik, Universität Giessen, Germany

In vacuum, QCD sum rules and vector meson dominance provide two important and successful concepts of hadron physics and its connection to QCD. QCD sum rules are designed to connect low-energy (hadronic) information with QCD perturbation theory improved by the inclusion of condensates. The vector meson dominance assumption states that all interaction of the photon with hadrons is mediated by vector mesons. It is shown that it is impossible that both concepts still hold in a nuclear environment. At least one of the two concepts must become invalid in the medium. The technical tools used for the purely analytical proof are weighted finite energy sum rules and dispersion relations for the forward scattering amplitude of an electromagnetic current on a nucleon.