A chameleon helioscope

Understand

Chameleon particles, which could explain dark energy, are in many ways similar to axions, suggesting that an axion helioscope can be used for chameleon detection.

• The distinguishing property of chameleon particles is that, unlike Standard Model particles, their effective masses depend upon the ambient matter-energy density.
• The associated total internal reflection of chameleons up to keV energies by a dense layer of material, which would occur at grazing incidence on the mirrors of an X-ray telescope, lead to new experimental techniques for detecting such particles.
• We discuss here when this total internal reflection can happen and how it can be implemented in existing or future state-of-the-art chameleon telescopes.