Exclusive production of ρ0ρ0 pairs in γγ collisions at RHIC

We discuss exclusive electromagnetic production of two neutral ρ mesons in coherent photon-photon processes in ultrarelativistic heavy-ion collisions. The cross section is calculated in the equivalent photon approximation (EPA). Both uncertainties of the flux factors and photon-photon cross sections are discussed in detail. We show that inclusion of precise charge densities in nuclei is essential for realistic evaluations of the nuclear photon-photon cross sections. We find that the cross section, especially with realistic flux factors, is sensitive to low energy in the subsystem γγ→ρ0ρ0. The experimental data for the γγ→ρ0ρ0 cross section extracted from e+e− collisions are parametrized and used to estimate the nucleus-nucleus cross section. In addition, we include vector-dominance-model (VDM)-Regge contribution which becomes important at large photon-photon energy. Large nuclear cross sections are obtained. We discuss a possibility of focusing on the large-energy component. We find that both ρ0 mesons are produced predominantly at midrapidities and could be measured by the STAR Collaboration at RHIC.