Highlights from Quark-Gluon Plasma Studies in Relativistic Nuclear Collisions

In the first microseconds after the Big Bang, the Universe passed through so called quark-gluon plasma (QGP) phase. The QGP is a hot and dense soup of quarks and gluons, basic constituents of the nuclear matter that interact via strong quantum chromo-dynamical (QCD) force. To recreate conditions that existed in the early Universe, we utilize powerful accelerators to conduct the collisions of nuclei in which drops of the QGP could be formed. Measuring of the QGP properties can be done only indirectly, via its remnants. Among the most important variables to study QGP properties appear azimuthal anisotropy and nuclear modification factor. Some of the corresponding results obtained at different collision energies, achieved at the LHC and SPS, are presented.