Exclusive Vector Meson Production in Relativistic Heavy Ion Collisions

Abstract

Exclusive vector meson production reactions such as $Au + Au \to Au + Au + V$, where $V=ρ, ω, ϕ$ or $J/ψ$ can proceed through photon-Pomeron and photon-meson interactions. Photons from the electromagnetic field of one nucleus interact coherently with the other nucleus. Photonuclear cross sections are scaled from $γp$ data, and convoluted with the photon spectrum to find the exclusive rates. The cross sections at the RHIC and LHC heavy ion colliders are huge, 10% of the total hadronic cross section at RHIC, and 50% at LHC. These accelerators may be useful as vector meson factories. With iodine beams at RHIC, 640 $ρ$ are produced each second (10^{10}/year); with calcium at the LHC the rate is 240 kHz. The $ϕ$ rates are 39 Hz at RHIC and 15 kHz at LHC, while the $J/ψ$ rate is 0.3 Hz at RHIC and 780 Hz at the LHC. Because of the coherent couplings, the reactions kinematics are similar to coherent two-photon interactions; we discuss the interplay between the two reactions.