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

## TL;DR

This study reports the first measurements of sub-threshold production of K0s mesons and Lambda hyperons in gold-gold collisions at 2.4 GeV, revealing universal strangeness scaling and challenging existing transport models.

## Contribution

First experimental data on sub-threshold strangeness production in Au+Au collisions at this energy, highlighting discrepancies with current transport model predictions.

## Key findings

- Universal strangeness scaling observed across hadrons.
- Transport models fail to simultaneously reproduce all measured observables.
- Data provides new constraints for theoretical models of sub-threshold particle production.

## Abstract

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.