Thermal Equilibration and Ellipsoidal Expansion of   Rotationally-Symmetrical Longitudinal Flow in Relativistc Heavy Ion   Collisions
  A rotationally-symmetrical ellipsoidal flow model is proposed for the relativistic heavy-ion collisions and compared with the 14.6 A GeV/c Si-Al and 10.8 A GeV/c Au-Au collision data. The large stopping in the heavier collision system and heavier produced particles is accounted for by using the ellipsoidal flow picture. The central dip in the proton and deuteron rapidity distributions for Si-Al collision are reproduced. 
Feng Shengqin, Liu Feng and Liu Lianshou