Antibaryon density in the central rapidity region of a heavy ion   collision
  We consider (anti-)baryons production in heavy ion collisions as production of topological defects during the chiral phase transition. Non-zero quark masses which explicitly break chiral symmetry supress the (anti-)baryon density. Hardly any (anti-)baryons will be produced in the central rapidity region of a heavy ion collision. 
J.Dziarmaga and M.Sadzikowski