One- and three-dimensional identical charged-kaon femtoscopic correlations in Pb-Pb collisions at s N N = 5.02 TeV

The identical charged-kaon correlations induced by quantum-statistics effects and final-state interactions are measured in Pb-Pb collisions at √𝑠𝑁⁢𝑁=5.02TeV. 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 𝑘T. The 1D parameters agree within uncertainties with those obtained in Pb-Pb collisions at √𝑠𝑁⁢𝑁=2.76TeV. 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 comoving 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.