Kaon polarizability in the Nambu-Jona-Lasinio model at zero and finite temperature

Using recent data for the decays f0 → γγ, f0 → ππ, we determine the mixing angle of scalar mesons in a chiral quark σ-model. This value is employed to analyze of the kaon polarizability. It is shown that pole diagrams from intermediate scalar mesons and their mixing angle significantly affect the electromagnetic polarizability of charged and neutral kaons. Our results are compared with other models and the results of the chiral symmetry limit. The temperature dependence of the kaon polarizabilities is investigated. Supported by Deutsche Forschungsgemeinschaft under contract 436 RUS 113/29. On leave of absence of Institut für Physik, Humboldt–Universität zu Berlin, Invalidenstraße 110, D–10115 Berlin, Germany