Conical Emission from Shock Waves in Ne(1-20 AGeV)+U Collisions

TL;DR

This paper investigates the formation of Mach shock waves and conical particle emission in high-energy Ne-U nucleus collisions using hydrodynamic simulations, highlighting differences from cascade models.

Contribution

It demonstrates the generation of conical emission from shock waves in nuclear collisions and compares hydrodynamic and cascade model predictions.

Findings

Conical emission occurs at the Mach cone angle in hydrodynamic simulations.

Angular distributions of baryons differ between hydrodynamic and cascade models.

Shock waves influence particle emission patterns in high-energy nuclear collisions.

Abstract

The formation and propagation of high-density compression waves, e.g. Mach shock waves, in cold nuclear matter is studied by simulating high-energy nucleus-nucleus collisions of Ne with U in the energy range from E_lab = 0.5 AGeV to 20 AGeV. In an ideal hydrodynamic approach, the high-density shock wave created by the small Ne nucleus passing through the heavy U nucleus is followed by a slower and more dilute Mach shock wave which causes conical emission of particles at the Mach cone angle. The conical emission originates from low-density regions with a small flow velocity comparable to the speed of sound. Moreover, it is shown that the angular distributions of emitted baryons clearly distinguish between a hydrodynamic approach and binary cascade processes used in the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) transport model.