Strangeness Production at 1 - 2 A GeV

TL;DR

This paper reviews strangeness production in heavy-ion collisions at 1-2 A GeV, highlighting how K+ and K- mesons serve as probes for nuclear matter properties and the collision dynamics.

Contribution

It provides a comprehensive comparison of experimental data with transport models, elucidating the production mechanisms and their implications for the nuclear equation of state.

Findings

K+ production occurs mainly during high-density phases via associate production.

K- mesons are predominantly produced through strangeness exchange and are absorbed before emission.

The nuclear matter is found to be relatively soft with a compressibility modulus below 240 MeV.

Abstract

The production of K+ and K- mesons below and at the NN threshold is summarized, based on a comparison of data with transport model calculations. K+ mesons are created in associate production together with hyperons (e.g. Lambda) in multi-step processes involving Delta resonances. These processes occur mainly during the high-density phase of the collision and this makes the K+ an ideal tool to extract the stiffness of the nuclear equation of state, found to be rather soft with a compressibility modulus K below 240 MeV. In contrast, the major part of K- mesons are produced via strangeness exchange. Most of the created K- are absorbed and the surviving ones are emitted quite late and at low densities.