By application of the pion electromagnetic form factor and also the P-wave isovector ππ scattering phase shift parametrizations, following from the first principles, like unitarity and analyticity, for a description of the corresponding accurate data, it is clearly demonstrated that the ρ0(770) meson mass and width values obtained by the Gounaris-Sakurai model in a description of the same data can not be accepted as correct ones.
Pion electromagnetic form factor with Minkowskian dynamics