This Letter presents the first measurement of event-by-event fluctuations of the net number (difference between the particle and antiparticle multiplicities) of multistrange hadrons $\Xi^-$ and $\overline{\Xi}^+$ and its correlation with the net-kaon number using the data collected by the ALICE Collaboration in pp, p$-$Pb, and Pb$-$Pb collisions at a center-of-mass energy per nucleon pair $\sqrt{s_{\mathrm{NN}}}=5.02\ \mathrm{TeV}$. The statistical hadronization model with a correlation over three units of rapidity between hadrons having the same and opposite strangeness content successfully describes the results. On the other hand, string-fragmentation models that mainly correlate strange hadrons with opposite strange quark content over a small rapidity range fail to describe the data.
Phys. Rev. Lett. 134, 022303 (2025)
HEP Data
e-Print: arXiv:2405.19890 | PDF | inSPIRE
CERN-EP-2024-151
Figure group
Figure 1
Normalized second order cumulant of net $\Xi$ (left panel) and correlation between net $\Xi$ and net kaon (right panel), as a function of the average multiplicity at midrapidity, in pp (red squares), p--Pb (green diamonds), and Pb--Pb collisions (blue circles) at $\sqrt{s_{\mathrm{NN}}}=5.02\ \mathrm{TeV}$. Statistical and systematic uncertainties are shown via error bars and boxes, respectively. The experimental measurements are compared to several model predictions, shown as bands. The width of the bands represents the statistical uncertainty of the predictions. The average multiplicity values are obtained from Refs. : their uncertainties are not shown in the plot. |   |
Figure A.1
Combined $\chi^2$ profile for the extraction of the correlation volume for baryon and strangeness conservation obtained by comparing the normalized second order net-$\Xi$ cumulants and the $\rho_{\Delta\Xi\Delta K}$ in Pb--Pb collisions to the Thermal-FIST predictions. The region close to the minimum $\chi^2$ is shown in the inset. The dashed line represents a fit to the $\chi^2$ profile with a fourth-degree polynomial function. |  |
Figure A.2
Comparison between the net-proton normalized second-order cumulant as a function of the average multiplicity at midrapidity measured by the ALICE Collaboration in Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV (blue circles) and the predictions of the Thermal-FIST model, with $T_{\mathrm{chem}}=155$ MeV and $V_{\mathrm{c}}=3\ \mathrm{d}V/\mathrm{dy}$ (orange band). |  |