Light Quark Energy Distribution in Heavy Quark Symmetry

Using heavy quark symmetry we construct an energy sum rule relating the form factor of a heavy flavored meson $\xi(w)$ to the light quark energy distribution. We find that the current available data for $\xi(w)$ is consistent with a broad energy distribution rather than with that of a pure quark/anti-quark bound state, indicating a large nonvalence content.