Speaker
Jean-Yves Ollitrault
(CNRS)
Description
The ATLAS collaboration has accurately measured elliptic flow, $v_2$, using multi-particle cumulants [arxiv:1408.4342], and observed for the first time a slight difference between $v_2\{4\}$ and $v_2\{6\}$. If the fluctuations of $v_2$ were Gaussian, all cumulants would coincide beyond order 4 [arXiv:0708.0800] therefore this measurement shows that $v_2$ fluctuations are slightly non-Gaussian. Elliptic flow is understood as a consequence as the hydrodynamic response to the initial eccentricity $\varepsilon_2$. Non-Gaussian $v_2$ fluctuations can be generated by non-Gaussian $\varepsilon_2$ fluctuations or by nonlinearities in the hydrodynamic response. We show that both mechanisms are likely to be important. We carry out event-by-event viscous hydrodynamic simulations and compare our results with ATLAS data.
| On behalf of collaboration: | None |
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Primary author
Jean-Yves Ollitrault
(CNRS)
Co-authors
Dr
Jacquelyn Noronha-Hostler
(University of Houston)
Li Yan
(CNRS)
