Speaker
Description
We use quasiparticle anisotropic hydrodynamics to study an azimuthally-symmetric boost- invariant quark-gluon plasma including the effects of both shear and bulk viscosities. In quasi- particle anisotropic hydrodynamics, a single finite-temperature quasiparticle mass is introduced and fit to the lattice data in order to implement a realistic equation of state. We compare results ob- tained using the quasiparticle method with the standard method of imposing the equation of state in anisotropic hydrodynamics and viscous hydrodynamics. Using these three methods, we extract the primordial particle spectra, total number of charged particles, and average transverse momentum for various values of the shear viscosity to entropy density ratio η/s. We find that the three methods agree well for small shear viscosity to entropy density ratio, η/s, but differ at large η/s. We find, in particular, that when using standard viscous hydrodynamics, the bulk-viscous correction can drive the primordial particle spectra negative at large pT which is clearly unphysical. Such a behavior is not seen in either anisotropic hydrodynamics approach, irrespective of the value of η/s.
