Has the QCD Critical Point been Signaled by Observations at RHIC ?
  The shear viscosity to entropy ratio ($\eta/s$) is estimated for the hot and dense QCD matter created in Au+Au collisions at RHIC ($\sqrt{s_{NN}}=200$ GeV). A very low value is found $\eta/s \sim 0.1$, which is close to the conjectured lower bound ($1/4\pi$). It is argued that such a low value is indicative of thermodynamic trajectories for the decaying matter which lie close to the QCD critical end point. 
Roy A. Lacey, N.N. Ajitanand, J.M. Alexander, P. Chung, W.G. Holzmann,   M. Issah, A. Taranenko (Stony Brook Univ.), P. Dani...