DRAFT: Photoproduction of the $\rho^0$ meson on the proton at large momentum transfer

TL;DR

This study measures the differential cross section for $ ho^0$ meson photoproduction on protons at high momentum transfer, revealing that multiple processes beyond simple models are needed to explain the data.

Contribution

It provides new high-momentum transfer data for $ ho^0$ photoproduction and shows the importance of including quark interchange processes in theoretical models.

Findings

Diffractive pattern observed at low -t consistent with Reggeon exchange.

At high -t, data deviates from two-gluon exchange predictions.

Quark interchange processes are significant at large momentum transfer.

Abstract

The differential cross section, $d\sigma/dt$, for $\rho^0$ 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 $\rho^0$ channel was extracted from the measured two charged-pion cross section by fitting the $\pi^+\pi^-$ and $p\pi^+$ 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 $\rho$ photoproduction.