Speaker
Dominik Karol Derendarz
(Polish Academy of Sciences (PL))
Description
The results from the detailed measurements of the azimuthal anisotropy of charged particles in lead-lead collisions at $\sqrt{s_{NN}} = $ 2.76 TeV and proton-lead collisions at $\sqrt{s_{NN}} = $ 5.02 TeV are presented. Various experimental methods were used to analyze high statistics data set collected by ATLAS experiment. Multi-particle cumulants provide a measurement of $v_{n}$ harmonics free from contributions not related to the initial geometry and give an estimate of event-by-event fluctuations of the flow harmonics. In lead-lead collisions second Fourier harmonic, $v_{2}$, was measured with two-, four-, six- and eight-particle correlation while $v_{3}$ and $v_{4}$ were extracted with four-particle cumulants. The distributions of event-by-event harmonic flow coefficients $v_{n}$ for n=2-4 were also measured in lead-lead collisions. Both approaches provides independent estimate of the event-by-event fluctuations of the flow harmonics and agrees well. Finally the collective behaviour of charged particles produced in the proton-lead collisions was studied by the measurements of $v_{n}$ harmonics associated with the azimuthal modulation of two-particle correlation structures and also extracted with four-particle cumulant method. These measurements give insight into the nature of fluctuations in the initial geometry and the role of hydrodynamic response to the fluctuations.
Author
Dominik Karol Derendarz
(Polish Academy of Sciences (PL))
