QCD sum rule analysis for light vector and axial-vector mesons in vacuum and nuclear matter

Extending previous work we study the constraints of QCD sum rules on mass and width of light vector and axial-vector mesons in vacuum and in a medium with finite nuclear density. For the latter case especially the effect of nuclear pions leading to vector-axial-vector mixing is included in the analysis. We examine the consequences of the mixing effect for positions and shapes of the peaks which show up in the current-current correlators. We also discuss the model dependences in the amount of mixing, in the evaluation of the four-quark condensate, and in the width parametrizations for the meson spectral functions.