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SUMMARY:Chameleon-photon mixing in a primordial magnetic field - Camilla S
 chelpe\, DAMTP
DTSTART:20100423T120000Z
DTEND:20100423T130000Z
UID:TALK24132@talks.cam.ac.uk
CONTACT:James Fergusson
DESCRIPTION:The chameleon scalar field has been proposed as a possible can
 didate for dark energy. The chameleon mechanism\, whereby the mass of the 
 scalar depends on the surrounding matter density\, allows the scalar field
  to have a strong coupling to normal matter and yet still evade fifth-forc
 e constraints. An extension of the original chameleon model includes a dir
 ect coupling between the chameleon and electromagnetic field. This generat
 es mixing between chameleons and photons in the presence of a background m
 agnetic field. Here we consider the modification to the average intensity 
 of the cosmic microwave background as a result of chameleon-photon mixing 
 in a primordial magnetic field. We find that comparison of these predictio
 ns to precision measurements of the CMB black-body spectrum places strong 
 constraints on the combined magnitude of the primordial magnetic field and
  chameleon-photon coupling strength.
LOCATION:Pavilion B Potter Room (B1.19)
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