Gießen 2007 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 20: Theorie
HK 20.6: Talk
Tuesday, March 13, 2007, 18:15–18:30, C
Nucleon and ω-Meson at Finite Density: The Role of Four-Quark Condensates in QCD Sum Rules — •Ronny Thomas1, Thomas Hilger2, Sven Zschocke3, and Burkhard Kämpfer1,2 — 1Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany — 2Institut für Theoretische Physik, TU Dresden, 01062 Dresden, Germany — 3TU Dresden, Lohrmann-Observatorium, 01062 Dresden, Germany
In-medium modifications of hadrons can be related to the density dependence of QCD condensates via QCD sum rules. The impact of the renormalization invariant combination mq ⟨ q q ⟩ in QCD sum rules for light vector mesons is numerically small. Instead, four-quark condensates essentially drive the change of spectral properties of light vector mesons embedded in nuclear matter. We present a generic catalog of four-quark condensates and compare the structures appearing in baryon and meson sum rules in the light quark sector. The nucleon self-energies at finite density are revisited and evaluations in this framework are compared to advanced nuclear matter calculations. For the ω-meson, qualitative findings in photoproduction data from the CB-TAPS collaboration are analyzed, cf. [1]. This allows to constrain the density dependence of special combinations of four-quark condensates.
[1] R. Thomas, S. Zschocke and B. Kämpfer, Phys. Rev. Lett. 95, 232301 (2005).