A new parametrization for the scalar pion form factors

Abstract

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 for B¯s0→J/ψππ. In particular we find for the pole positions of f0(1500) and f0(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) %.