In this paper the production of K⁺, K^- and \phi mesons in Al+Al collisions at incident beam energy of 1.9A GeV is studied. The experiment was performed in GSI/Darmstadt using the FOPI spectrometer. The K^-/K⁺ yields ratio was extracted in a substantial part of the phase-space. The yields ratio was found to be in a good agreement with previous experimental results that served as a proof for in-medium modifications of kaons' properties. In order to quantify the contribution of \phi mesons decays to the observed K^- mesons yield, the \phi meson production probability was estimated. The preliminary result differs by almost two orders of magnitude from the earlier estimate available for heavier (Ni+Ni) system at similar beam energy, in which the number of K^- mesons that could stem from \phi mesons decays was found to be as high as 20\%.

PACS numbers: 25.75.--q, 25.75.Dw