2012/07/03 by Radosław Ryblewski, Ryblewski, Radoslaw · 1 citation
Physics and Astronomy · #Cosmology and Gravitation Theories #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Nuclear Theory (nucl-th) #Quantum Chromodynamics and Particle Interactions #Statistical Mechanics and Entropy
paper · pdf · doi:10.48550/arxiv.1207.0629
openalex publication_date 2012/07/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A recently developed framework of highly-anisotropic and strongly-dissipative\nhydrodynamics -- ADHYDRO -- has been introduced and used to analyze the\nspace-time evolution of matter produced in ultra-relativistic heavy-ion\ncollisions. The main goal of this analysis was to study the effect of initial\nhighly-anisotropic stages on the final soft hadronic observables typically\nmeasured in the experiment. The study was done in the context of the heavy-ion\nmeasurements performed at RHIC (Relativistic Heavy Ion Collider) in Brookhaven\nNational Laboratory. Starting from the general assumption about the form of the\nphase-space distribution function, thermodynamic properties of locally\nanisotropic systems of particles have been studied and the form of the\ngeneralized equation of state has been formulated. The dynamic equations\ndetermining the evolution of a highly-anisotropic fluid have been introduced.\nThe form of the entropy source related to the mechanisms leading to\nthermalization of the system has been defined. In the simplest case of\npurely-longitudinal and boost-invariant expansion, different features of the\nmodel have been analyzed. Using the ADHYDRO model in the general (3+1)D and\nboost-invariant (2+1)D versions, different possible scenarios of early stages\nof heavy-ion collisions have been analyzed. The results of the ADHYDRO model\nhave been compared to the results obtained from the reference, perfect-fluid\nhydrodynamic model -- LHYQUID. The results of the hydrodynamic models were\ncoupled to the statistical Monte-Carlo model THERMINATOR. The following\nconclusions have been drawn: a) All studied observables are almost insensitive\nto the initial anisotropic stage provided the initial conditions of the\nevolution are properly readjusted, b) Complete thermalization of matter may\ntake place only at the times of about 1 fm/c. In this way the early\nthermalization puzzle may be circumvented.\n