Quark Matter 2018

Scalar product and event plane methods for measurements of azimuthal anisotropy in Pb+Pb and Xe+Xe collisions with the ATLAS detector at the LHC

15 May 2018, 17:00

2h 40m

First floor and third floor (Palazzo del Casinò)

Poster Correlations and fluctuations Poster Session

Speaker

Klaudia Burka (Polish Academy of Sciences (PL))

Description

Measurements of the azimuthal anisotropy of charged particles in heavy-ion collisions are sensitive to the detailed properties of the quark-gluon plasma, in particular its dependence on initial conditions, transport coefficients and time evolution. The presented measurements are based on 0.49 n${\mathrm{b}}^{-1}$ of Pb+Pb data collected by the ATLAS detector in 2015 with center-of-mass energy $\sqrt{s_{NN}}=5.02$ TeV. The elliptic flow and higher-order Fourier coefficients ($v_2$ - $v_7$) are presented in a wide range of transverse momenta ($p_{\mathrm{T}}<60$ GeV), pseudorapidity ($|\eta |<2.5$) and 0-80% collision centrality. The collected minimum-bias sample is enhanced by triggers for "ultra-central" collisions, providing an opportunity to perform precise measurements of flow harmonics in the fluctuation-dominated regime. The magnitude of azimuthal anisotropy is estimated by measuring the angular correlations of produced particles using both the scalar product and event plane methods. To suppress non-flow, $v_n$ harmonics are calculated by correlating two flow vectors estimated in two different detectors separated in pseudorapidity (the forward calorimeter $3.2<|\eta |<4.8$, or the inner detector $|\eta |<2.5$), and in the opposite hemispheres. The obtained results are compared to the $v_n(p_{\mathrm{T}})$ values at measured in $\sqrt{s_{NN}}=2.76$ TeV Pb+Pb collisions and recent $\sqrt{s_{NN}}=5.44$ TeV Xe+Xe collisions as well as to predictions of hydrodynamical models.

Presentation materials

KBurka-QMposter.pdf