Sub-threshold production of K^{0}_{s} mesons and {Lambda} hyperons in Au(1.23A GeV)+Au

We present first data on sub-threshold production of K0 s mesons and {Lambda} hyperons in Au+Au collisions at $sqrt{s_{NN}}$ = 2.4 GeV. We observe an universal <Apart> scaling of hadrons containing strangeness, independent of their corresponding production thresholds. Comparing the yields, their <Apart> scaling, and the shapes of the rapidity and the pt spectra to state-of-the-art transport model (UrQMD, HSD, IQMD) predictions, we find that none of the latter can simultaneously describe all observables with reasonable c{hi}2 values.