Strangeness at high temperatures: from hadrons to quarks

TL;DR

This study uses lattice QCD to analyze strangeness fluctuations at high temperatures, revealing a transition from hadronic to quark-gluon plasma states and indicating deconfinement occurs at the chiral crossover.

Contribution

It provides detailed lattice QCD analysis of strangeness degrees of freedom across the QCD transition, highlighting the breakdown of hadronic descriptions and the emergence of quark behavior.

Findings

Hadronic description valid up to the chiral crossover

Deconfinement of strangeness occurs at the chiral crossover

Quark-gluon plasma exhibits strongly interacting features in the intermediate temperature range

Abstract

Appropriate combinations of up to fourth order cumulants of net strangeness fluctuations and their correlations with net baryon number and electric charge fluctuations, obtained from lattice QCD calculations, have been used to probe the strangeness carrying degrees of freedom at high temperatures. For temperatures up to the chiral crossover separate contributions of strange mesons and baryons can be well described by an uncorrelated gas of hadrons. Such a description breaks down in the chiral crossover region, suggesting that the deconfinement of strangeness takes place at the chiral crossover. On the other hand, the strangeness carrying degrees of freedom inside the quark gluon plasma can be described by a weakly interacting gas of quarks only for temperatures larger than twice the chiral crossover temperature. In the intermediate temperature window these observables show considerably richer structures, indicative of the strongly interacting nature of the quark gluon plasma.