Phenomenological predictions of 3+1d anisotropic hydrodynamics

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

Nopoush, Mohammad^1 ; Strickland, Michael^1 ; Ryblewski, Radoslaw^2

Department of Physics, Kent State University, Kent

OH

44242, United States^1

Institute of Nuclear Physics, Polish Academy of Sciences, Krakow

PL-31342, Poland^2

关键词: Dynamical equation;    Equation of state;    Freeze out temperature;    Heavy ion collision;    Particle production;    Particle spectra;    Relaxation time approximation;    Transverse momenta;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/832/1/012054/pdf
DOI  :  10.1088/1742-6596/832/1/012054

来源: IOP

【 摘 要 】

We make phenomenological predictions for particle spectra and elliptic flow in heavy-ion collisions using 3+1d anisotropic hydrodynamics (aHydro) including the effects of both shear and bulk viscosities. The dynamical equations necessary are derived by taking moments of the Boltzmann equation allowing for three distinct (diagonal) momentum-space anisotropy parameters. The formulation is based on relaxation-time approximation for the collisional kernel and a lattice-QCD-based equation of state. Evolving the system to late times, we calculate particle production using THERMINATOR 2, modified to account for an ellipsoidal distribution function. We obtain particle spectra for different particle species such as pions, kaons, and protons, and elliptic flow v2as a function of centrality, transverse momentum, and rapidity. In our model, we have four free parameters, i.e. freeze-out temperature, initial central energy density, initial momentum-space anisotropies, and shear viscosity to entropy density ratio. Using a multidimensional fit to LHC experimental data, we make a preliminary extraction of these parameters. We find reasonable agreement between 3+1d aHydro and available experimental data for η/s ∼ 0:23.