Percolation line of stable clusters in supercritical fluids
  We predict that self-bound clusters of particles exist in the supercritical phase of simple fluids. These clusters, whose internal temperature is lower than the global temperature of the system, define a percolation line that starts at the critical point. This line should be physically observable. Possible experiments showing the validity of these predictions are discussed. 
X. Campi, H. Krivine and N. Sator