In heavy-ion collisions at ultrarelativistic energies an extreme state of deconfined nuclear matter, the quark-gluon plasma (QGP), can be produced. One of the most informative probes to access its properties is the anisotropic flow phenomenon. An important ongoing program in the field is the development of new observables and analysis techniques for anisotropic flow measurements, which would be sensitive only to one particular stage at a time in the heavy-ion evolution. By using the recently developed flow observables, called higher-order symmetric cumulants, the genuine event-by-event correlations between three flow amplitudes are measured for the first time in Pb-Pb collisions by the ALICE Collaboration at the Large Hadron Collider. These results can provide new and independent constraints on the initial conditions and the properties of the QGP created in heavy-ion collisions. In a recent theoretical work, the mathematical formalism of multivariate cumulants is combined with the usage of cumulants in flow analyses. This points to the next generation of observables to be used in flow analyses. Based on these results, we discuss future directions of anisotropic flow studies, both on the experimental and theoretical frontier.
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Meeting ID: 984 5733 2925
Peter Thirolf (LMU) / Norbert Kaiser (TUM)