Influence of a temperature-dependent shear viscosity on the azimuthal asymmetries of transverse momentum spectra in ultrarelativistic heavy-ion collisions

Physical Review C (Impact Factor: 3.73). 03/2012; 86(1). DOI: 10.1103/PhysRevC.86.014909
Source: arXiv


We study the influence of a temperature-dependent shear viscosity over
entropy density ratio $\eta/s$, different shear relaxation times $\tau_\pi$, as
well as different initial conditions on the transverse momentum spectra of
charged hadrons and identified particles. We investigate the azimuthal flow
asymmetries as a function of both collision energy and centrality. The elliptic
flow coefficient turns out to be dominated by the hadronic viscosity at RHIC
energies. Only at higher collision energies the impact of the viscosity in the
QGP phase is visible in the flow asymmetries. Nevertheless, the shear viscosity
near the QCD transition region has the largest impact on the collective flow of
the system. We also find that the centrality dependence of the elliptic flow is
sensitive to the temperature dependence of $\eta/s$.


Available from: Gabriel S. Denicol, Mar 13, 2014
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    • "Since the early days of ideal hydrodynamics there has been a concerted effort to make hydrodynamical models more realistic by including the effect of shear and bulk viscosities (relaxation times). This has lead to a proper formulation of relativistic viscous hydrodynamics [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] and, recently, anisotropic relativistic viscous hydrodynamics [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29]. The conclusion one reaches from dissipative hydrodynamics approaches is that the QGP created in ultrarelativistic heavy ion collisions (URHICs) has quite different longitudinal (along the beam line) and transverse pressures, particularly at times τ ∼ < 2 fm/c. "
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    • "The inclusion of dissipative effects in the description of the QGP started only a few years ago. To date the majority of studies have focused on investigating the effects of the shear viscosity in the time evolution of the QGP and in extracting its magnitude from HIC measurements [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21]. Nevertheless, there are other sources of dissipation that might play a role in the fluid-dynamical description of HIC, such as bulk viscous pressure and heat flow. "
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