Chasing the onset of strange-quark thermalization at the LHC

This note presents the first measurement of event-by-event fluctuations of the net-$\Xi^\pm$ number and of its correlation with the net-kaon number. The study is based on data collected by the ALICE Collaboration in pp, p$-$Pb, and Pb$-$Pb collisions at a center-of-mass energy per nucleon--nucleon pair $\sqrt{s_{\mathrm{NN}}}=5.02\ \mathrm{TeV}$. A negative correlation between net-$\Xi^\pm$ and net-kaon numbers is observed across different colliding systems. Predictions obtained with the canonical thermal-statistical model, as implemented in Thermal-FIST, agree with the experimental results throughout the analyzed multiplicity range. On the other hand, models based on the string-fragmentation mechanism, e.g. PYTHIA and HIJING, fail to describe the data. The selected observables are sensitive to the correlation volume for the strangeness and baryon number conservation, which is also estimated.