Speaker
Prof.
Volker Metag
Description
Chiral symmetry is a fundamental symmetry of Quntum Chromodynamics (QCD) in the limit of vanishing quark masses. In the hadronic sector chiral symmetry is broken; otherwise chiral partners – hadronic states with the same spin but opposite parity - should be degenerate in mass which is not observed in nature. It has been suggested that chiral symmetry might at least partially be restored in a strongly interacting environment. As a consequence properties of hadrons, encoded in their mass and width, may be modified in the medium. These ideas have motivated widespread theoretical and experimental activities. (For recent reviews of the field see 1-3).
The talk will summarize the status of recent experimental results on the search for in-medium modifcations of hadrons in photon and proton induced reactions using the CBELSA/TAPS detector at the electron accelerator ELSA (Bonn), the Crystal Ball at MAMI (Mainz), and the HADES detector at GSI (Darmstadt). Results on the light vector mesons ρ, ω and the pesudoscalar η’ meson will be presented.
References:
[1] S. Leupold, V. Metag, U. Mosel, Int. J. Mod. Phys. E 19 (2010) 147.
[2] R. Hayano and T. Hatsuda, Rev. Mod. Phys. 82 (2010) 2949.
[3] R. Rapp, J. Wambach, H. Van Hees, Landolt Börnstein, New Series I/23A (2010) 4-1.
