Momentum anisotropy at freeze out

Workshop for young scientists on the physics of ultrarelativistic nucleus-nucleus collisions 2016

Feld, S.^1 ; Borghini, N.^1 ; Lang, C.^1

Universität Bielefeld, Fakultät für Physik, Bielefeld, Germany^1

关键词: A-particles;    Fluid evolution;    Freeze out temperature;    High energy heavy-ion collision;    Hydrodynamical model;    Last stage;    Local phase;    Momentum spaces;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/832/1/012053/pdf
DOI  :  10.1088/1742-6596/832/1/012053

来源: IOP

【 摘 要 】

The transition from a hydrodynamical modeling to a particle-based approach is a crucial element of the description of high-energy heavy-ion collisions. Assuming this "freeze out" happens instantaneously at each point of the expanding medium, we show that the local phase-space distribution of the emitted particles is asymmetric in momentum space. This suggests the use of anisotropic hydrodynamics for the last stages of the fluid evolution. We discuss how observables depend on the amount of momentum-space anisotropy at freeze out and how smaller or larger anisotropies allow for different values of the freeze-out temperature.