Energy dependence of φ meson production in central Pb+Pb collisions at √=6 to 17 GeV

Abstract

φ meson production is studied by theNA49Collaboration in central Pb + Pb collisions at 20A, 30A, 40A, 80A, and 158A GeV beam energy. The data are compared with measurements at lower and higher energies and with microscopic and thermal models. The energy dependence of yields and spectral distributions is compatible with the assumption that partonic degrees of freedom set in at low SPS energies.