Vector mesons in pions and kaon form factors

The method for calculation of pion and kaon form factors and electromagnetic radii in the q2-approximation is given. It is shown that in the tree approximation and q2-approximation we have to consider the same set of diagrams (contact and vector-pole diagrams); and only using the vector meson form factor we can obtain equivalent results in both cases, which agree with the experimental data. The form factors of vector meson decays into two pions (kaons) play a very important role if these processes are considered off the mass shell of vector mesons. The q2-approximation is useful for investigation of the intrinsic properties of mesons, particularly, their behaviour in a hot medium. Some conclusions concerning the temperature behaviour of meson electromagnetic radii are drawn. 17 refs., 10 figs., 1 tab