Sub-leading flow modes in PbPb collisions at √sNN =2.76 TeV from HYDJET++ model

• Published in: EPJ Web of Conferences 2018-01, Vol.182, p.2086
• Main Authors: Milosevic, Jovan, Cirkovic, Predrag, Devetak, Damir, Dordevic, Milos, Stojanovic, Milan
• Format: Article
• Language: English
• Subjects: Collisions; Computational fluid dynamics; Correlation analysis; Dependence; Fluid flow; Hydrodynamics; Mathematical models; Ponds; Principal components analysis; Transverse momentum; Variations
• ISSN: 2100-014X; 2101-6275; 2100-014X
• DOI: 10.1051/epjconf/201818202086

The LHC results on the sub-leading flow modes in PbPb collisions at 2.76 TeV, related to initial-state fluctuations, are analyzed and interpreted within the HYDJET++ model. Using the newly introduced Principal Component Analysis (PCA) method applied to two-particle azimuthal correlations extracted from the model calculations, the leading and the sub-leading flow modes are studied as a function of the transverse momentum (pT ) over a wide centrality range. The leading modes of the elliptic (v (1) 2 ) and triangular (v 3 (1) 3) flow calculated within the HYDJET++ model reproduce rather well the v 2 {2} and v 3 {2} coeffcients experimentally measured using the two-particle correlations. Within the pT ≤3 GeV/c range where hydrodynamics dominates, the sub-leading flow effects are greatest at the highest pT of around 3 GeV/c. The sub-leading elliptic flow mode (v 2 (2) ), which corresponds to n=2 harmonic, has a small non-zero value and slowly increases from central to peripheral collisions, while the sub-leading triangular flow mode (v 3 (2) ), which corresponds to n =3 harmonic, is even smaller and does not depend on centrality. For n =2, the relative magnitude of the effect measured with respect to the leading flow mode shows a shallow minimum for semi-central collisions and increases for very central and for peripheral collisions. For n =3 case, there is no centrality dependence. The subleading flow mode results obtained from the HYDJET++ model are in a rather good agreement with the experimental measurements of the CMS Collaboration.