Electromagnetic self-energies of neutral pions: contributions from vector resonances

By employing vector-meson dominance to establish the electromagnetic interactions of hadrons, the electromagnetic self-energy of the neutral pions, which receives the contributions from the vector resonances due to chiral anomaly, is evaluated. This part of the electromagnetic mass, which can contribute to the mass difference of π±–π0, is finite and as expected, is smaller than the contributions due to isospin symmetry breaking and electromagnetic chiral logs corrections, however, could be compared with the contribution from the short-distance QCD.