Skewness of the elliptic flow distribution in $\sqrt{s_{{}_{\mathrm{NN}}}}$ = 5.02~TeV PbPb collisions from HYDJET++ model

Abstract

The elliptic flow ($v_2$) event-by-event fluctuations in PbPb collisions at 5.02~TeV are analyzed within the HYDJET++ model. Using the multi-particle, so called Q-cumulant method, $v_2\{2\}$, $v_2\{4\}$, $v_2\{6\}$ and $v_2\{8\}$ are calculated and used to study their ratios and to construct skewness (${\gamma }_1^{exp}$) as a measure of the asymmetry of the elliptic flow distribution. Additionally, in order to check if there is a hydrodynamics nature in the elliptic collectivity generated by the HYDJET++ model, the ratio of $v_2\{6\}-v_2\{8\}$ and $v_2\{4\}-v_2\{6\}$ distribution is calculated. The analysis is performed as a function of the collision centrality. In order to check the HYDJET++ model responses, the results of this analysis are compared to the corresponding experimental measurements by CMS. A good qualitative and rather good quantitative agreement is found.