Search for Signal on Percolation Cluster Formation in Nucleus-Nucleus Collisions at Relativistic Energies

TL;DR

This study investigates the formation of percolation clusters in nucleus-nucleus collisions at relativistic energies, providing experimental evidence that supports the role of percolation in the mixed phase formation of strongly interacting matter.

Contribution

The paper offers new experimental confirmation of percolation cluster formation as an accompanying effect of the mixed phase in nuclear matter during high-energy collisions.

Findings

Percolation cluster formation influences nuclear fragment characteristics.

Regime changes in particle behavior suggest large percolation cluster formation.

Centrality can be defined via target and projectile fragment counts.

Abstract

The appearance of the strongly interacting matter mixed phase (MP)has been suggested to consider to understand qualitatively the regime change existence in the behavior of some centrality depending characteristics of events. The MP has been predicted by QCD for the temperatures around the critical temperature Tc and could be formed as a result of nucleon percolation in the density nuclear matter. Our main goal is to get a new experimental confirmation of the percolation cluster formation as an accompanying effect of the MP formation. To reach the goal, the experimental data on Kr+Em - reaction at 0.95 GeV/nuc and Au+Em - reaction at 10.6 GeV/nucl. with a number of target fragments N_h > 8, have been analyzed. The behavior of the distributions of the target and the projectile fragments has been studied. The experimental data have been compared of the data coming from the cascade-evaporation model. We can conclude that: -- the centrality of the collision could be defined as a number of the target g-fragments in Kr+Em reactions at energies 0.95 A GeV/nucl and as a number of projectile F-fragments with Z>=1 in Au + Em reactions at energies 10.6 A GeV/nucl; -- the formation of the percolation cluster sufficiently influences the characteristics of nuclear fragments; -- there are points of the regime changes in the behavior of some characteristics of $s$-particles as a function of centrality which could be qualitatively understood as a result of the big percolation cluster formation.