Omega mesons in medium - revisited

Abstract

Recent experimental observation by the CBELSA/TAPS collaboration indicates a downward mass shift of the $\omega$ meson when put into a nuclear medium. Therefore it is worthwhile to take a look at theoretical approaches that can describe this mass shift. One such hadronic model was introduced by Klingl et al. (Nucl.Phys. A650:299-312). We will demonstrate that the heavy baryon limit approximation used there has no justification and returns wrong results. The results obtained with a correct treatment of the relevant $2\pi$-channel lead to unreasonable results for the $\omega$ selfenergy in medium.