$\phi$ puzzle in heavy-ion collisions at 2 A GeV: how many K$^-$ from $\phi$ decays?
Résumé
The preliminary experimental data on $\\phi$ production in the reaction Ni(1.93 AGeV) + Ni point to a puzzling high $\\phi$ yield which can not be reproduced with present transport codes. We survey the experimental situation and present prospects for dedicated measurements of the $\\phi$ multiplicities with the $K^+ K^-$ and $e^+ e^-$ channels at HADES and FOPI.