We derive a new parametrization for the scalar pion form factors that allows us to analyze data over a large energy range via the inclusion of resonances, and at the same time to ensure consistency with the high-accuracy dispersive representations available at low energies. As an application the formalism is used to extract resonance properties of excited scalar mesons from data forB 0 s → J/ψππ. In particular we find for the pole positions of f 0 (1500) and f 0 (2020) 1465±18−i(50±9) MeV and 1910±50−i(199±40) MeV, respectively. In addition, from their residues we calculate the respective branching ratios into ππ to be (58 ± 31)% and (1.3 ± 1.8)%.

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We present a new parametrization for scattering amplitudes and form factors, which is consistent with high-accuracy dispersive representations at low energies but at the same time allows for a data description of higher mass resonances such as the f0(1500) and f0(2020). The formalism is general and thus can be applied to many decay processes. As an example we discuss the decay of $ \bar {B}_s^0 $ → J/ψππ(KK). From the amplitude fixed in a fit to the experimental data pole positions and residues are extracted via Padé approximants.