Precise determination of the parameters of resonances f0(500) and f0(980) by fitting the data and dispersion relations

Abstract

The long-standing puzzle in the parameters of the f0(500), as well as the f0(980), is finally being settled [1] thanks to precise dispersive analyses carried out during the last years. Here we report on our very recent dispersive data analysis which allowed for a precise and model independent determination of the amplitudes for the S, P, D and F waves [2–4]. The analytic continuation of once subtracted dispersion relations for the S0 wave to the complex energy plane leads to very precise results for the f0(500) pole: √spole = 457-13+14 - i279-7+11 MeV and for the f0(980) pole: √spole = 996 ± 7 - i25-6+10 MeV.