Indication of anomalous exchange in exclusive charmonium photoproduction

Abstract

We find that available data on $J/Ψ$ photoproduction at $|t|{\ge}$1 GeV are energy independent over the range $22{\le}\sqrt{s}{\le}170$ GeV and show a very soft $t$ dependence. Through a systematic analysis of the data we detect a new trajectory, which manifests itself at threshold and is energy independent. The trajectory couples to the axial form factor of the nucleon and can reproduce the $J/Ψ$ exclusive photoproduction data at large -$t$.

5 pages, 4 figures