Chameleon dark energy models are a popular alternative to the standard cosmological constant model. These models consist of a new light degree of freedom, called chameleon, with a density dependent mass and a non-trivial coupling to both matter and photons. Owing to these couplings, chameleons can be produced inside the sun. However due to their density dependent mass, the chameleons produced in the solar core are screened and cannot escape whereas those produced outside the solar core, such as in the \textit{tachocline} region with energies of the order of few a keV, can escape from the sun and travel all the way towards Earth. Hence the Earth is expected to receive a flux of \textit{solar chameleons}. In this work we propose a \textit{light shining through wall} (LSW) type of experiment in which the Earth itself acts as a wall. Both photons and chameleons are incident on the light side of the Earth. While all the photons are stopped by the Earth, only a fraction of the chameleons are stopped by the earth due to screening. Those chameleons which are not screened by the earth pass directly through the Earth and exit the night side. Here these chameleons interact with the geomagnetic field and convert into X-ray photons. A space based X-ray telescope orbiting the Earth can detect these X-ray photons, while passing through the night side, thereby acting as a detector in this LSW type experiment. We show that such a kind of setup can be complementary to other terrestrial experiments looking for chameleons.
Bounds on screened dark energy from near-Earth space-based measurements
Università di Salerno（萨莱诺大学）；INFN, Sezione di Napoli（意大利国家核物理研究所那不勒斯分部）；Institut de Physique Théorique, Université Paris-Saclay, CEA, CNRS（巴黎萨克雷大学理论物理研究所）
The Arthur B. McDonald Canadian Astroparticle Physics Research Institute, Department of Physics, Engineering Physics, and Astronomy, Queen’s University（阿瑟·B·麦克唐纳加拿大天体粒子物理研究所，女王大学物理、工程物理和天文学系）；Perimeter Institute for Theoretical Physics（理论物理珀蒂默研究所）；Department of Physics and McDonnell Center for the Space Sciences, Washington University（华盛顿大学物理系和麦克唐纳空间科学中心）；The Arthur B. McDonald Canadian Astroparticle Physics Research Institute, Department of Physics McGill University（阿瑟·B·麦克唐纳加拿大天体粒子物理研究所，麦吉尔大学物理系）
