Abstract
We have measured the differential cross section for the and reactions at in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at exhibit a global scaling behavior for both and photoproduction, consistent with the constituent counting rule and the existing photoproduction data. Possible oscillations around the scaling value are suggested by these new data. The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive to photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.
- Received 8 November 2002
DOI:https://doi.org/10.1103/PhysRevLett.91.022003
©2003 American Physical Society