Systematic study of flow vector fluctuations in sNN =5.02 TeV Pb-Pb collisions

Acharya S., Adamová D., Agarwal A., Aglieri Rinella G., Aglietta L., Agnello M., ...More

Physical Review C, vol.109, no.6, 2024 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 109 Issue: 6
  • Publication Date: 2024
  • Doi Number: 10.1103/physrevc.109.065202
  • Journal Name: Physical Review C
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, INSPEC
  • Yıldız Technical University Affiliated: Yes


Measurements of the pT-dependent flow vector fluctuations in Pb-Pb collisions at sNN=5.02TeV using azimuthal correlations with the ALICE experiment at the Large Hadron Collider are presented. A four-particle correlation approach [ALICE Collaboration, Phys. Rev. C 107, L051901 (2023)2469-998510.1103/PhysRevC.107.L051901] is used to quantify the effects of flow angle and magnitude fluctuations separately. This paper extends previous studies to additional centrality intervals and provides measurements of the pT-dependent flow vector fluctuations at sNN=5.02TeV with two-particle correlations. Significant pT-dependent fluctuations of the V - 2 flow vector in Pb-Pb collisions are found across different centrality ranges, with the largest fluctuations of up to ∼15% being present in the 5% most central collisions. In parallel, no evidence of significant pT-dependent fluctuations of V - 3 or V - 4 is found. Additionally, evidence of flow angle and magnitude fluctuations is observed with more than 5σ significance in central collisions. These observations in Pb-Pb collisions indicate where the classical picture of hydrodynamic modeling with a common symmetry plane breaks down. This has implications for hard probes at high pT, which might be biased by pT-dependent flow angle fluctuations of at least 23% in central collisions. Given the presented results, existing theoretical models should be reexamined to improve our understanding of initial conditions, quark-gluon plasma properties, and the dynamic evolution of the created system.