Speaker
Jean-Yves Ollitrault
(CNRS)
Description
The ATLAS collaboration has recently shown that anisotropic flow exhibits a strong centrality dependence in ultracentral collisions [arXiv:1904.04808]. In particular, the 4-particle cumulant of elliptic flow changes sign, and the centrality at which this change of sign occurs depends on the observable which is used to determine the centrality. We show that these features are universal consequences of impact parameter fluctuations within a centrality bin. More precisely, they naturally follow from the fact that the relation between the impact parameter and the experimentally-determined centrality is not one to one.
Author
Jean-Yves Ollitrault
(CNRS)
Co-author
Giuliano Giacalone
(Université Paris-Saclay)
