Phi Mesons from a Hadronic Fireball

Abstract

Production of $\phi$ mesons is considered in the course of heavy-ion collisions at SPS energies. We investigate the possible difference in momentum distributions of $\phi$ mesons measured via their leptonic ($\mu^+\mu^-$) and hadronic ($K^+K^-$) decays. Rescattering of secondary kaons in the dense hadron gas together with the influence of in-medium kaon potential can lead to a relative decrease of a $\phi$ yield observed in the hadronic channel. We analyze how the in-medium modifications of meson properties affect apparent - reconstructed momentum distributions of $\phi$ mesons. Quantitative results are presented for central Pb+Pb collisions at $E_{beam}=158 GeV/A$.