Comment on 'Two-photon decay width of the sigma meson'

  title={Comment on 'Two-photon decay width of the sigma meson'},
  author={Eef van Beveren and Frieder Kleefeld and George Erik Rupp and Michael D. Scadron},
  journal={Physical Review D},
We comment on a recent paper by Giacosa, Gutsche, and Lyobovitskij [Phys. Rev. D 77, 034007 (2008)], in which it is argued that a quarkonium interpretation of the $\ensuremath{\sigma}$ meson should give rise to a much smaller two-photon decay width than commonly assumed. The reason for this claimed discrepancy is a term in the transition amplitude, necessary for gauge invariance, which allegedly is often omitted in the literature, including the work of the present authors. Here we show their… 
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