Photoproduction of phi(1020) mesons on the proton at large momentum transfer

TL;DR

This paper reports the first measurement of phi meson photoproduction cross sections on the proton at large momentum transfer, revealing a transition from Pomeron exchange to a two-gluon exchange model.

Contribution

It provides new experimental data at high momentum transfer and supports a model where the Pomeron is resolved into two gluons at large -t values.

Findings

Differential cross section matches Pomeron exchange at low -t.

At high -t, data supports a two-gluon exchange model.

First measurement of phi photoproduction at large momentum transfer.

Abstract

The cross section for $\phi$ meson photoproduction on the proton has been measured for the first time up to a four-momentum transfer -t = 4 GeV^2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. At low four-momentum transfer, the differential cross section is well described by Pomeron exchange. At large four-momentum transfer, above -t = 1.8 GeV^2, the data support a model where the Pomeron is resolved into its simplest component, two gluons, which may couple to any quark in the proton and in the $\phi$.