Coherent Coupling to both nuclei: photon ? Z2, Pomeron ?A4/3 to A 2 ( A4/3 in the limit srN?? ; A2 in the weak limit)
Coherent Coupling to both nuclei: photon ? Z2, Pomeron ?A4/3 to A 2 ( A4/3 in the limit srN?? ; A2 in the weak limit)
Large cross section: 380 mb for Au@130Gev/nuclon
Small transverse momentum: pT ~2hg/RA~ 60 MeV
Nuclei may be mutually excited
Ultra-Peripheral Collisions
Exclusive production of r0 mesons Au+Au --> Au+Au + r0
Two nuclei ‘miss’ each other and interact via their photon fields at impact parameters b > 2RA