Speaker
Dr
brijesh srivastava
(Purdue University)
Description
The shear to viscosity ratios ($\eta/s$) are obtained for the QGP in the context of the Color String Percolation Model (CSPM) using data produced in Au-Au collisions at $\sqrt{s_{NN}}$ = 200 A GeV at RHIC and Pb-Pb at $\sqrt{s_{NN}}$ = 2.76 TeV at LHC \cite{per}. The experimental transverse momentum spectrum is used to measure the percolation density parameter $\xi$ in Au-Au collisions (STAR)\cite{eos}. The relativistic kinetic theory relation for $\eta/s$ is evaluated using CSPM values for the temperature and the mean free path of the QGP constituents \cite{gul1}.
For Pb-Pb at $\sqrt{s_{NN}}$ = 2.76 TeV, $\xi$ values are obtained from the extrapolation at RHIC energy. The value of $\eta/s$ is 0.204$\pm$ 0.020 and 0.262$\pm$0.026 at the initial temperatures of 193.6 MeV (RHIC) and 262.2 MeV (LHC), respectively. These values are 2.3 and 3.2 times the AdS/CFT conjectured lower bound $1/4\pi$ but are consistent with the theoretical estimates of strongly coupled QGP.
Primary author
Dr
brijesh srivastava
(Purdue University)
Co-authors
Dr
Andy Hirsch
(Purdue University)
Jorge Dias de Deus
(Instituto Superior Tecnico)
Dr
Rolf scharenberg
(Purdue university)
carlos Pajares
(University Santiago)
