Color dipole phenomenology of diffractive electroproduction of light vector mesons at HERA

We develop the color dipole phenomenology of diffractive photoand electroproduction γ∗ N → V (V ′)N of light vector mesons (V (1S) = φ0, ω0, ρ0) and their radial excitations (V ′(2S) = φ′, ω′, ρ′). The node of the radial wave function of the 2S states in conjunction with the energy dependence of the color dipole cross section is shown to lead to a strikingly different Q2 and ν dependence of diffractive production of the V (1S) and V ′(2S) vector mesons. We discuss the restoration of flavor symmetry and universality properties of production of different vector mesons as a function of Q+mV . The color dipole model predictions for the ρ 0 and φ0 production are in good agreement with the experimental data from the EMC, NMC, ZEUS and H1 collaborations. We present the first direct evaluation of the dipole cross section from these data. E-mails: [email protected] [email protected] [email protected] [email protected]