Measurement of two-particle Bose-Einstein momentum correlations and their Levy parameters at $\sqrt{s_{_{\mathrm{NN}}}}=5.02$ TeV PbPb collisions

Charged hadron, two-particle Bose-Einstein momentum correlation functions in lead-lead (PbPb) collisions at an average center of mass energy per nucleon ($\sqrt{s_{_{\mathrm{NN}}}}$) of 5.02 TeV are presented. The data were obtained in 2018 by the CMS experiment at the LHC. The experimental results are discussed in terms of theoretically derived correlation functions for Levy type source distributions. Using average pair transverse momentum and centrality binning, the source distribution parameters are extracted as a function of pair transverse mass $m_{\mathrm{T}}$ and collision centrality. These parameters include the correlation strength parameter $\lambda$, the Levy index or shape parameter $\alpha$, and the Levy scale parameter $R$. We find that the source shape, characterized by $\alpha$, is neither Cauchy nor Gaussian, implying the need for a full Levy analysis. A hydrodynamical scaling, previously shown to work for Gaussian radii, is also found to hold for $R$.