Current predictions for the ratio of phi -> K^+K^-/K_LK_S decay rates exceed the corresponding experimental value in about five standard deviations. By far, the dominant sources of isospin breaking to this ratio are the phase-space (52%) and the elec
tromagnetic radiative (4.3%, computed within scalar QED) corrections. Here we estimate the effects of the electromagnetic structure of kaons and other model-dependent contributions into the radiative corrections.
We compute the difference in decay widths of charged and neutral rho(770) vector mesons. The isospin breaking arising from mass differences of neutral and charged pi and rho mesons, radiative corrections to rho -> pipi, and the rho -> pipigamma decay
s are taken into account. It is found that the width difference Delta Gamma_rho is very sensitive ot the isospin breaking in the $rho$ meson mass Delta m_rho. This result can be useful to test the correlations observed between the values of these parameters extracted from experimental data.
