Solar Chameleons

TL;DR

This paper explores how chameleons produced inside the sun can convert into detectable photons in the soft X-ray range, offering a new method to identify dark energy candidates with solar observations.

Contribution

It demonstrates the potential of using solar X-ray flux and helioscopes like CAST to detect chameleons, a dark energy candidate, through their unique photon conversion signatures.

Findings

Chameleons can produce a soft X-ray photon flux matching solar flux.

Back-converted photons have orthogonal polarization to axion photons.

Detection of chameleons could be feasible with upgraded CAST detectors.

Abstract

We analyse the creation of chameleons deep inside the sun and their subsequent conversion to photons near the magnetised surface of the sun. We find that the spectrum of the regenerated photons lies in the soft X-ray region, hence addressing the solar corona problem. Moreover, these back-converted photons originating from chameleons have an intrinsic difference with regenerated photons from axions: their relative polarisations are mutually orthogonal before Compton interacting with the surrounding plasma. Depending on the photon-chameleon coupling and working in the strong coupling regime of the chameleons to matter, we find that the induced photon flux, when regenerated resonantly with the surrounding plasma, coincides with the solar flux within the soft X-ray energy range. Moreover, using the soft X-ray solar flux as a prior, we find that with a strong enough photon-chameleon coupling the chameleons emitted by the sun could lead to a regenerated photon flux in the CAST pipes, which could be within the reach of CAST with upgraded detector performance. Then, axion helioscopes have thus the potential to detect and identify particles candidates for the ubiquitous dark energy in the universe.