One- and three-dimensional identical charged-kaon femtoscopic correlations in Pb--Pb collisions at $\mathbf{ \sqrt{s_\mathrm{NN}}=5.02}$ TeV

TL;DR

This study measures charged-kaon femtoscopic correlations in Pb-Pb collisions at 5.02 TeV, revealing system size and collective flow effects, and compares results with model predictions to understand particle emission dynamics.

Contribution

It provides new 1D and 3D femtoscopic measurements at 5.02 TeV and compares them with models, highlighting the evolution of emission times and system sizes across collision centralities.

Findings

System size parameters decrease with collision peripheralness.

3D radii follow a power-law dependence on pair transverse momentum.

Kaons are emitted earlier in more peripheral collisions.

Abstract

The identical charged-kaon correlations induced by quantum-statistics effects and final-state interactions are measured in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV. The results of one- (1D) and three-dimensional (3D) analyses show that the obtained system-size parameters (radii) are smaller for more peripheral collisions and decrease with increasing pair transverse momentum $k_{\rm T}$. The 1D parameters agree within uncertainties with those obtained in Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV. The observed power-law dependence of the extracted 3D radii as a function of the pair transverse momentum is a signature of the collective flow in the particle-emitting system created in Pb$-$Pb collisions. This dependence is well reproduced by the integrated hydrokinetic model calculations except for the outward projection of the radius (measured in the longitudinally co-moving system) for the most central collisions. The time of maximal emission for kaons is extracted from the 3D analysis in a wide collision centrality range from 0 to 90%. Its reduction with decreasing charged-particle multiplicity is well reproduced by the hydrokinetic model predictions, and means that kaons are emitted earlier in more peripheral events.