Two photon decays of scalar mesons in the quark NJL model
Abstract
Two photon decays of scalar mesons f0(980), a0(980), σ(600) in the quark Nambu - Jona - Lasinio (NJL) model are calculated. The contributions of the meson loops are taken into account along with the quark loops (Hartree - Fock approximation). This corresponds to the next order of the 1/Nc expansion, where Nc=3 is the number of quark colors. It is shown that the meson and quark loops give comparable contributions to the amplitude. Moreover, in the process f0(980)-> γ γ the kaon loop plays the dominant role. A similar situation takes place in the decay φ -> f0(980) γ physrev. Our results are in satisfactory agreement with the recent experimental data.
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