Photoproduction of the ρ⁰ meson on the proton at large momentum transfer

The differential cross section, dσ/dt, for ρ⁰ meson photoproduction on the proton above the resonance region was measured up to a momentum transfer −t = 5GeV² using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The ρ⁰ channel was extracted from the measured two charged-pion cross sections by fitting the π⁺π⁻ and pπ⁺ invariant masses. The low momentum transfer region shows the typical diffractive pattern expected from Reggeon exchange. The flatter behavior at large −t cannot be explained solely in terms of QCD-inspired two-gluon exchange models. The data indicate that other processes, like quark interchange, are important to fully describe ρ photoproduction.