Unraveling the f₀ nature by connecting KLOE and BABAR data through analyticity

We define a general procedure, based on analyticity and dispersion relations, to estimate low energy amplitudes for processes like: ϕ → e⁺e^-M and ϕ → γM, starting from cross section data on e⁺e^- → ϕM, where M is a generic light scalar or pseudoscalar meson. In particular this procedure is constructed to obtain predictions on the radiative decay rate which are crucially linked on the assumed quark structure for the meson M under consideration.

Three cases are analyzed: M = η, and . While in the η case the estimate of the branching fraction for the radiative decay ϕ → ηγ is in agreement with the data, in the case of f₀, such agreement is obtained only under the hypothesis of a tetraquark scalar meson.