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Quantifying the BICEP2-Planck tension over gravitational waves.
Kendrick M Smith1, Cora Dvorkin2, Latham Boyle1
1Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5, Canada.
Physical Review Letters
|August 2, 2014
Summary
The BICEP2 experiment detected a signal possibly from primordial gravity waves, but it conflicts with WMAP and Planck data. Further analysis will clarify if this tension signals new physics or is a statistical anomaly.
Area of Science:
- Cosmology
- Astrophysics
- Cosmic Microwave Background Radiation
Background:
- The BICEP2 experiment measured B-mode polarization in the cosmic microwave background, potentially indicating primordial gravity waves.
- This measurement (r = 0.2) shows tension with upper limits from WMAP (r < 0.13) and Planck (r < 0.11).
Purpose of the Study:
- To quantify the statistical significance of the tension between BICEP2 and other cosmic microwave background measurements.
- To explore potential explanations for this tension, including statistical flukes or new physics beyond the standard cosmological model.
Main Methods:
- Statistical analysis to quantify the tension, considering the deficit of large-scale temperature power.
- Proposing future measurements of TE and EE power spectra to differentiate between hypotheses.
Main Results:
- The tension between BICEP2 and WMAP/Planck data is statistically significant (around 0.1% unlikely) when large-scale temperature power deficits are included.
- Future TE and EE power spectra measurements are crucial for distinguishing between a statistical fluke and new physics.
Conclusions:
- The observed tension may indicate new physics beyond the standard cosmological model.
- Extensions to the standard model are discussed as potential resolutions, along with novel constraints.
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