%0 Journal Article
%T Bound-state effects in ¦Ì^+ e^- \to ¦Ã¦Ãand \bar{B}^{0}_s \to ¦Ã¦Ãdecays
%A J. O. Eeg
%A K. Kumericki
%A I. Picek
%J Physics
%D 2000
%I arXiv
%R 10.1007/s100520000471
%X We demonstrate that in the double-radiative decays of heavy-light QED and QCD atoms, \mu^{+} e^{-} \to \gamma\gamma and \bar{B}^{0}_{s} \to \gamma\gamma, there is a contribution coming from operators that vanish on the free-quark mass shell. This off-shell effect is suppressed with respect to the effect of the well known flavour-changing magnetic-moment operator by the bound-state binding factor. Accordingly, the negligible off-shellness of the weakly bound QED atoms becomes important for strongly bound QCD atoms. We present this effect in two different model-approaches to QCD, one of them enabling us to keep close contact to the related effect in QED.
%U http://arxiv.org/abs/hep-ph/0007183v1