Testing Parity-Violating Interactions with CMB Experiments
Abstract
The Standard Model (SM) violates parity (P) within the weak sector, presumably because it is a low-energy limit of some grand unified theory. Since physics beyond the SM is required to explain the observed cosmology, there is a possibility that nature also violates parity through gravity or other yet undiscovered sectors. Considerable interest has been dedicated to two classes of P-violating interactions beyond the SM: chiral gravity, with parity odd Chern-Simons terms in the action, and quintessence models that couple to the pseudo-scalar of electromagnetism, manifesting themselves as cosmological birefringence. These mechanisms can produce non-vanishing P-breaking correlations in CMB temperature and polarization maps, opening the possibility of measurement through cosmological experiments.
We develop the full-sky formalism for estimating the amount of direction-dependent rotation of the CMB polarization due to quintessence effects, and we calculate constraints on the rotation angle multipoles for different instrumental resolutions and noise levels. We use a similar formalism to calculate the constraints on chirality of primordial gravitational waves that could be obtained with different instruments. Finally, we combine the two P-violating mechanisms and calculate the constraints on the joint parameter space. We find that data with WMAP sensitivity yield no constraint on gravitational chirality, and put an upper limit of 2 degrees on uniform rotation from quintessence, consistent with previous results. We explore how the allowed parameter space changes in the case of non-detection with Planck, SPIDER, and CMBPol.- Publication:
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American Astronomical Society Meeting Abstracts #215
- Pub Date:
- January 2010
- Bibcode:
- 2010AAS...21540703G