Measuring Negative Energy Dilaton Particles

Measured dilaton particles have negative energy because they support one-way ``superluminal'' group velocity data. Dilaton particles are modeled as negative energy excitations of a dark energy field. These excitations saturate the Ford-Roman Quantum Inequality (QI) below the cutoff energy value required to stabilize the vacuum aginst decay through a negative energy channel. The QI saturates near the dark energy density value required to drive the observed accelerated expansion rate of the universe.