Reaction Plane In Heavy-ion Collisions Research Articles

The PSD CBM Supermodule Response Study for Hadrons in Momentum Range 2 – 6 GeV/c at CERN Test Beams

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Chiral Effects in Nucleus–Nucleus Collisions: Experimental Review

A survey of experimental results obtained by studying chiral effects in nucleus–nucleus collisions at various energies is presented. The entire body of these experimental results confirms indirectly a topologically nontrivial structure of the QCD vacuum and the possibility of a local violation of discrete QCD symmetries at finite temperature. A significant decrease in the asymmetry of the distribution of electrically charged particles with respect to the reaction plane in heavy-ion collisions in the energy range of $$\sqrt {sNN} $$ GeVmay be indicative of a possible transition to the region where hadron states dominate over quark–gluon degrees of freedom in a mixed phase formed in nucleus–nucleus collisions at intermediate energies.

DEPENDENCE OF ASYMMETRIES FOR CHARGE DISTRIBUTION WITH RESPECT TO THE REACTION PLANE ON INITIAL ENERGY IN HEAVY-ION COLLISIONS

In this paper, two combinations of correlators are defined in order to investigate the evolution of possible [Formula: see text] invariance violation in strong interactions with initial energy for heavy-ion collisions. These combinations correspond to absolute and relative asymmetry of distribution of electrically charge particles with respect to the reaction plane in heavy-ion collisions. Energy dependence of parameters under study was derived from data of STAR and ALICE experiments. Significant decreasing both absolute and relative asymmetry is observed at energies [Formula: see text]. This feature agrees qualitatively with other results of stage-I beam energy scan program in STAR experiment. General behavior of dependence of absolute asymmetry on initial energy agrees reasonably with behavior of similar dependence of Chern–Simons diffusion rate calculated at different values of external Abelian magnetic field. The observed behavior of parameters under study versus energy can be considered as indication on possible transition to predominance of hadronic states over quark–gluon degrees of freedom in the mixed phase created in heavy-ion collisions at intermediate energies.

Disappearance of flow.

We investigate the disappearance of collective flow in the reaction plane in heavy-ion collisions within a microscopic model (QMD). A systematic study of the impact parameter dependence is performed for the system Ca+Ca. The balance energy strongly increases with impact parameter. Momentum dependent interactions reduce the balance energies for intermediate impact parameters $b\approx4.5$ fm. Dynamical negative flow is not visible in the laboratory frame but does exist in the contact frame for the heavy system Au+Au. For semi-peripheral collisions of Ca+Ca with $b\approx6.5$ fm a new two-component flow is discussed. Azimuthal distributions exhibit strong collectiv flow signals, even at the balance energy.