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Chameleons with Field Dependent Couplings

Certain scalar-tensor theories exhibit the so-called chameleon mechanism, whereby observational signatures of scalar fields are hidden by a combination of self-interactions and interactions with ambient matter. Not all scalar-tensor theories exhibit such a chameleon mechanism, which has been origina...

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Detalles Bibliográficos
Autores principales: Brax, Philippe, van de Bruck, Carsten, Mota, David F, Nunes, Nelson J, Winther, Hans A
Formato: info:eu-repo/semantics/article
Lenguaje:eng
Publicado: Phys. Rev. D 2010
Materias:
Acceso en línea:https://dx.doi.org/10.1103/PhysRevD.82.083503
http://cds.cern.ch/record/1272125
Descripción
Sumario:Certain scalar-tensor theories exhibit the so-called chameleon mechanism, whereby observational signatures of scalar fields are hidden by a combination of self-interactions and interactions with ambient matter. Not all scalar-tensor theories exhibit such a chameleon mechanism, which has been originally found in models with inverse power run-away potentials and field independent couplings to matter. In this paper we investigate field-theories with field-dependent couplings and a power-law potential for the scalar field. We show that the theory indeed is a chameleon field theory. We find the thin-shell solution for a spherical body and investigate the consequences for E\"ot-Wash experiments, fifth-force searches and Casimir force experiments. Requiring that the scalar-field evades gravitational tests, we find that the coupling is sensitive to a mass-scale which is of order of the Hubble scale today.