Study of heavy ion collisions at ultra high energies represents a major subject in the contemporary nuclear and particle physics. The fundamental motivation is to understand the properties of the new state of matter known as quark-gluon plasma which is predicted by Quantum Chromo-Dynamics to occur at very high temperatures and energy densities. In this work the ALICE experiment at LHC in CERN measured the azimuthal distribution of particles and found that the plasma behaves as a viscous fluid.
Aamodt, K. ; Abelev, B. ; Quintana, A.A. ; Adamová, Dagmar ; Bielčíková, Jana ; Kushpil, Svetlana ; Kushpil,
Vasilij ; Mareš, Jiří A. ; Polák, Karel ; Šumbera, Michal ; Závada, Petr, Phys.Rev.Lett. 105 (2010) 252302.