Bonn 2020 – wissenschaftliches Programm
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HK 36.5: Vortrag
Mittwoch, 1. April 2020, 17:45–18:00, J-HS H
Using spectators to probe anisotropic flow fluctuations in Pb-Pb collisions with ALICE at the LHC — •Lukas Kreis for the ALICE collaboration — GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt — Ruprecht-Karls-Universität Heidelberg
In heavy-ion collisions, the fluctuating phase-space distribution of the participant and spectator nucleons results in anisotropic flow fluctuations of the produced particles. Before the quark-gluon plasma is formed, the deflection of the spectators is imprinted in the initial energy-momentum distribution in the overlap zone. The pattern of flow fluctuations can be determined by comparing flow coefficients measured relative to the plane defined by the spectator deflection to those measured relative to the participant plane. These two measurements should exhibit the same behaviour for central and semi-central collisions and differ for peripheral, according to calculations, in which anisotropic flow fluctuations emerge from Gaussian fluctuations of initial spatial eccentricity. In this presentation, ALICE measurements of the anisotropic flow in Pb–Pb collisions relative to the spectator deflection are presented. The deflection is determined using the Zero Degree Calorimeter. Together with ALICE measurements of two and multi-particle cumulant methods this allows to probe flow fluctuations and their deviation from the Gaussian shape.