Detecting chameleons: The astronomical polarization produced by chameleonlike scalar fields
- Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, Cambridge CB3 0WA (United Kingdom)
- Queen Mary University of London, Astronomy Unit, School of Mathematical Sciences, Mile End Road, London E1 4NS (United Kingdom)
We show that a coupling between chameleonlike scalar fields and photons induces linear and circular polarization in the light from astrophysical sources. In this context chameleonlike scalar fields include those of the Olive-Pospelov (OP) model, which describes a varying fine structure constant. We determine the form of this polarization numerically and give analytic expressions in two useful limits. By comparing the predicted signal with current observations we are able to improve the constraints on the chameleon-photon coupling and the coupling in the OP model by over 2 orders of magnitude. It is argued that, if observed, the distinctive form of the chameleon induced circular polarization would represent a smoking gun for the presence of a chameleon. We also report a tentative statistical detection of a chameleonlike scalar field from observations of starlight polarization in our galaxy.
- OSTI ID:
- 21260013
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 79, Issue 4; Other Information: DOI: 10.1103/PhysRevD.79.044028; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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