The phase transition to the quark-gluon plasma and its effect on hydrodynamic flow

Abstract

It is shown that in ideal relativistic hydrodynamics a phase transition from hadron to quark and gluon degrees of freedom in the nuclear matter equation of state leads to a minimum in the excitation function of the transverse collective flow.

Effects of the QCD phase transition on hadronic observables in relativistic hydrodynamic simulations of heavy-ion reactions in the FAIR/NICA energy regime

“…Secondly, it exhibits a pronounced maximum at around 4 AGeV. In contrast, the bag model equation of state renders the minimum of the directed flow at around 6 AGeV which perfectly coincides with the results of [16], where this minimum had been proposed as a qualitative signal for the transition of hadronic matter to quark and gluon degrees of freedom. The reason is, of course, the extreme softening of the equation of state in the mixed phase, as can bee seen from Fig.…”

“…Excitation functions of the directed flow have been studied in [16] as a possible way of probing the equation of state of nuclear matter in a fluid-dynamic model. These calculations not take into account hadronic freeze-out -as most of the early studies -and relayed directly on the analysis of the energy momentum tensor of the baryonic fluid.…”

“…At low energies, the hydrodynamic picture of a single fluid describing the interaction of projectile and target nuclei has been used early on to study collective effects like directed flow and the dependence of these effects on the nuclear equation of state (see, e. g. [13,14,16]). Spectra of secondary particles, however, have rarely been analyzed in a purely hydrodynamic description of low energy heavy ion collisions, a notable exception being the two-fluid model approach of [17].…”

Phase transitions and critical behavior in hadronic transport with a relativistic density functional equation of state

“…The search for signatures of the QCD critical point is premised on the ability to experimentally uncover a number of effects born out in systems of immense complexity. Some of these predicted signatures involve light nuclei * agnieszka.sorensen@gmail.com production [9,10], enhanced multiplicity fluctuations of produced hadrons [11][12][13], the slope of the directed flow [14,15], or Hanbury-Brown-Twiss (HBT) interferometry measurements [16], and their dependence on the beam energy. Often, the magnitudes of these effects and their interaction with various other experimental signals, as well as the influence of the finite time of the collision or baryon number conservation remain elusive to purely theoretical predictions.…”

Identifying the nature of the QCD transition in relativistic collision of heavy nuclei with deep learning

“…Currently some observables, for example, anisotropic flow [24][25][26][27], directed flow [28,29] and fluctuations of particle multiplicities [30][31][32][33], are conjectured as most sensitive to the appearance of a phase transition. Furthermore, modern statistical methods are used to apply a global fitting of a set of different observables with Bayesian methods [34,35].…”