Kaon modification in hot hadronic matter

We calculate the momentum-dependent potentials (both real and imaginary parts) for K mesons propagating in hot hadronic matter. If the matter is sufficiently dulute, collisions are binary and we may use experimentally known scattering amplitudes. Therefore, our results are essentially model-independent. The meson-induced potential is about twice as large as that found previously using only the K^*(892) resonance. The interaction with nucleons is attractive for K^- and further increases the potential, but is repulsive for K⁺, significantly compensating the mesonic contribution at break-up conditions at AGS. We also discuss the effect of the kaon potential on the width of φ meson decaying inside the matter. In particular, the K⁺ emerges with momentum which is slightly larger than that of K^-.