Production of QED pairs at small impact parameter in relativistic heavy   ion collisions
  The STAR collaboration at RHIC is measuring the production of electron-positron pairs at small impact parameters, larger than but already close to the range, where the ions interact strongly with each other. We calculate the total cross section, as well as, differential distributions of the pair production process with the electromagnetic excitation of both ions in a semiclassical approach and within a lowest order QED calculation. We compare the distribution of electron and positron with the one coming from the cross section calculation without restriction on impact parameter. Finally we give an outlook of possible results at the LHC. 
Kai Hencken (1), Gerhard Baur (2), Dirk Trautmann (1), ((1) U Basel,   (2) FZ Juelich)