28 July 2020 to 6 August 2020
virtual conference
Europe/Prague timezone

Constraining the transport properties of quark-gluon plasma with latest flow measurements in ALICE

31 Jul 2020, 12:36
24m
virtual conference

virtual conference

Talk 07. Heavy Ions Heavy Ions

Speaker

Vytautas Vislavicius (University of Copenhagen (DK))

Description

Collisions of relativistic heavy ions at the LHC are carried out to understand the fundamental properties of one of the extreme phases of QCD matter, the quark-gluon plasma (QGP). Anisotropic flow is one of the most sensitive probes to study the QGP transport properties, such as the shear viscosity over entropy density ratio (η/s), the value of which was found to be close to a universal lower bound for any liquid set by the AdS/CFT theory. However, the temperature dependence of η/s is poorly constrained. In addition, the choice of initial conditions or determination of other properties, such as the bulk viscosity or hadron momentum distribution at freeze-out, affects the resulting values of η/s extracted from hydrodynamical model comparisons to the data. Therefore, more sensitive measurements able to scrutinise the individual parameters are of great interest.

The ALICE detector plays a leading role in performing state-of-the-art measurements to characterise the properties of the QGP at the LHC. In this talk, we will present measurements of anisotropic flow, its fluctuations, and recently developed observables such as symmetric cumulants, non-linear flow modes, and correlations among symmetry planes. Both unidentified charged particles and identified hadrons were used for the analysis, using the unique identification capabilities of the ALICE detector among the LHC experiments. Comparison of these measurements to recent hydrodynamic calculations allow for unprecedented constraints of the initial conditions and the temperature dependence of the shear and bulk viscosities of the QGP, which was not feasible with earlier flow measurements. The complexity of these measurements, together with several model comparisons, will bring invaluable insight into the geometry of the fluctuating initial state and the dynamical evolution of the hot and dense medium produced in ultra-relativistic heavy-ion collisions.

Primary author

Vytautas Vislavicius (University of Copenhagen (DK))

Presentation materials