Relativistic Hydrodynamic Simulations of Directed Flow Instabilities in Asymmetric Germanium-Gold Collisions

International Journal of Physics | Vol. 15, No. 12, December 2024 | pp. 89–96

DOI: 10.46882/2024/IJP/000176

Research Article

Title: Relativistic Hydrodynamic Simulations of Directed Flow Instabilities in Asymmetric Germanium-Gold Collisions

Names of Authors: S. C. O’Brien¹, A. M. El-Chemali²

Authors’ Affiliations:
¹ School of Physics, University College Dublin, Dublin, Ireland
² Department of Physics, Faculty of Science, Lebanese University, Beirut, Lebanon

Abstract: High-energy asymmetric nuclear collisions provide an exceptional experimental platform to probe initial-state spatial geometry fluctuations and check the minimum boundary limits required to form a transient droplet of quark-gluon plasma. This study presents a relativistic hydrodynamic simulation framework to model particle production cascades and evaluate directed flow instabilities in germanium-gold (Ge-Au) collisions at a center-of-mass energy of 200.0 GeV per nucleon pair. We utilized a 3+1 dimensional viscous hydrodynamic code coupled with a statistical hadronization module to calculate final-state transverse momentum spectra. The initial energy density distributions were generated via a Monte Carlo Glauber model to track sub-nucleon scale configurations. The numerical simulations show that expanding fireballs develop a substantial radial flow profile, shifting the mean transverse momentum of protons up to 1.18 GeV/c in central events. The calculated directed flow coefficient (v1) displays a strong mass-ordering signature, which matches experimental tracking data from specialized heavy-ion detectors within a tight ±5.5% margin. This agreement implies that small-scale asymmetric nuclear interaction zones can briefly sustain fluid-like collective expansion profiles. These findings clarify the boundary constraints of fluid behavior in high-energy physics.

Keywords: Relativistic hydrodynamics; quark-gluon plasma; directed flow; asymmetric collisions; Glauber model; statistical hadronization

Manuscript Timeline: Received: September 15, 2024; Revised: October 30, 2024; Accepted: November 15, 2024; Published: December 16, 2024

Citation: O’Brien, S. C., & El-Chemali, A. M. (2024). Relativistic Hydrodynamic Simulations of Directed Flow Instabilities in Asymmetric Germanium-Gold Collisions. International Journal of Physics, 15(12), 89–96.

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