Speaker
Description
Recent advancements in multi-parameter model-to-data comparison have provided notable constraints on the temperature dependence of the shear viscosity over entropy density ratio $\eta/s$ in the matter produced in the Pb+Pb collisions at the LHC. The results of the Bayesian analysis with a flexible initial state parametrization [1,2] support a linear temperature dependence of $\eta/s$ found in the earlier study using the EKRT pQCD + saturation + hydrodynamics model [3]. However, it remains unexplored how much the choice of the equation of state affects the final outcome of the global analysis.
We perform a global model-to-data comparison on Au+Au and Pb+Pb collisions at $\sqrt{s_{NN}}=200$ GeV, $2.76$ TeV and $5.02$ TeV, using a hydrodynamics model with the EKRT initial state, and the same parametric form for $\eta/s(T)$ as in Ref. [3]. To quantify the amount of uncertainty incorporated in the choice of EoS, we compare analysis results based on three different equations of state: the well known s95p parametrisation [4], an updated parametrisation based on the same list of particles, but recent lattice results [5] for the partonic EoS, and an updated parametrisation based on the Particle Data Group 2016 particle list and the recent lattice results.
References:
[1] Bernhard et al., Phys. Rev. C 94, 024907 (2016), arxiv:1605.03954
[2] Bass et al., Nucl.Phys. A 967, 67 (2017), arXiv:1704.07671
[3] Niemi et al., Phys. Rev. C 93, 024907 (2016), arxiv:1505.02677
[4] Huovinen and Petreczky, Nucl. Phys. A 837, 26 (2010), arXiv:0912.2541
[5] Bazavov et al., arXiv:1710.05024 and
Bazavov et al., Phys. Rev. D 90, 094503 (2014), arXiv:1407.6387 and
Borsanyi et al., Phys. Lett. B 730, 99 (2014), arXiv:1309.5258
