Precise Determination of the f0(600) and f0(980) Pole Parameters from a Dispersive Data Analysis

We use our latest dispersive analysis of pi pi scattering data and the very recent K-l4 experimental results to obtain the mass, width, and couplings of the two lightest scalar-isoscalar resonances. These parameters are defined from their associated poles in the complex plane. The analytic continuation to the complex plane is made in a model-independent way by means of once-and twice-subtracted dispersion relations for the partial waves, without any other theoretical assumption. We find the f(0)(600) pole at (457(-13)(+14)) - i(279(-7)(+11)) MeV and that of the f(0)(980) at (996 +/- 7) - i(25(-6)(+10)) MeV, whereas their respective couplings to two pions are 3.59(-0.13)(+0.11) and 2.3 +/- 0.2 GeV.