In-medium effects in ϕ-meson production in heavy ion collisions from subthreshold to relativistic energies

Abstract

We investigate the hidden strange φ meson production in heavy-ion collisions from subthreshold (Ekin ∼ 1AGeV) to relativistic (Ekin ∼ 21ATeV) energies as well as its coupling to the open strange mesons (kaons, antikaons) and their productions. Our study is based on the off-shell microscopic Parton-Hadron-String Dynamics (PHSD) transport approach. Implementing novel meson-baryon and meson-hyperon production channels for φ mesons, calculated within a T-matrix coupled channel approach based on the extended SU(6) chiral effective Lagrangian model, along with the collisional broadening of the φ-meson in-medium spectral function, we find a substantial enhancement of φ meson production in heavy-ion collisions, especially at sub- and near-thresholds. This allows to describe the experimentally observed strong enhancement of the φ/K− ratio at low energies without including hypothetical decays of heavy baryonic resonances to φ as in alternative approaches