DRAFT: Photoproduction of the $\ddot{I}{}^0$ meson on the proton at large momentum transfer

Abstract

The differential cross section, $d\ddot{I}ƒ/dt$, for $\ddot{I}{}^0$ meson photoproduction on the proton above the resonance region ($2.6<W<2.9$ GeV) was measured up to a momentum transfer $-t=5$ GeV${}^2$ using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The $\ddot{I}{}^0$ channel was extracted from the measured two charged-pion cross section by fitting the $\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ and $p\ddot{I}{€}^{+}$ 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 $\ddot{I}$ photoproduction.

submitted to PRL, 5pages, 4 figures