ω and rho Photoproduction with an Effective Quark Model Lagrangian

An unified approach for vector meson photoproduction is presented in the constit quark model. The s- and u-channel resonance contributions are generated using an effective quark vector-meson Lagrangian. In addition, taking into account $\pi^0$ and $\sigma$ t-channel exchanges for diffractive production, the available total and differential cross section data for $\omega$, $\rho^0$, $\rho^+$, and $\rho^-$ photoproduction can be well described with the same quark model parameter set. Our results clearly indicate that polarization observables are essential to identify so-called "missing" resonances.