  We show that the asymmetry in the fractional energy of charm versus anticharm
jets produced in high energy diffractive photoproduction is sensitive to the
interference of the Odderon $(C = -)$ and Pomeron $(C = +)$ exchange amplitudes
in QCD. We predict the dynamical shape of the asymmetry in a simple model and
estimate its magnitude to be of the order 15% using an Odderon coupling to the
proton which saturates constraints from proton-proton vs. proton-antiproton
elastic scattering. Measurements of this asymmetry at HERA could provide firm
experimental evidence for the presence of Odderon exchange in the high energy
limit of strong interactions.
