News on strangeness production from the NA61/SHINE experiment

¹ National Centre for Nuclear Research, Pasteura 7 str., 02-093 Warsaw, Poland
² Ruder Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia

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Published online: 17 April 2026

Abstract

Strangeness production in high-energy hadronic and nuclear collisions continues to be one of the central topics in the study of strongly interacting matter. The data collected by the NA61/SHINE experiment at the CERN SPS North Area allow for a comprehensive scan of the strangeness production across various collision energies and system sizes.

This article focuses on the new results of the strangeness production in central collisions of medium-sized nuclei, such as Ar+Sc, at the SPS energy range. In particular, the results for Lambda hyperons and charged and neutral K mesons are shown. The energy and system size dependencies of Lambda-to-pion and strangeness-to-pion ratios are also explored. Moreover, an unexpected excess of charged over neutral K meson production in Ar+Sc and π⁻+C interactions is presented. The obtained results are compared with predictions from selected particle production models, as well as with existing world data from protonproton and nucleus-nucleus collisions.