Search for $a_0(980)$ and $f_0(980)$ mesons in $\phi\to\gamma K\bar K$

Abstract

We study the decay $\phi\to\gamma K^+K^-$ taking into account the scalar mesons production $\phi\to\gamma(f_0+a_0) \to\gamma K^+K^-$ and the final state radiation. We note that the relative sign between the final state radiation amplitude and the scalar meson production amplitude is fixed in the $K^+K^-$ loop model which describes data on the $\phi\to \gamma f_0\to\gamma\pi\pi$ and $\phi\to\gamma a_0\to\gamma\pi\eta$ decays. As consequence this model predicts the definite interference between the final state radiation and the scalar resonance production amplitudes. We calculate the mass spectra of the $\phi\to\gamma K^+K^-$ decay and the differential cross-sections for $e^+e^-\to\phi\to\gamma K^+K^-$ and for $e^+e^-\to\phi\to\gamma K^0\bar K^0$ reactions.