LAMBDA Graphics: Upper Limits on the Tensor to Scalar Power Ratio

A measurement of the tensor to scalar power ratio, r, would constrain the energy scale of inflation. There is no detection at present, but recent limits on r, evaluated at a pivot scale of 0.05 Mpc-1, are shown in the following plot. This graphic is not intended to illustrate a complete history, but rather provides a snapshot of current upper limits as experiments continue to search for a detection. Please acknowledge LAMBDA when using these images.


BICEP2/Keck 2018 (arXiv, ADS)
Planck PR4 2020 (arXiv)

A service of the HEASARC and of the Astrophysics Science Division at NASA/GSFC
Goddard Space Flight Center, National Aeronautics and Space Administration
HEASARC Director: Dr. Alan P. Smale
LAMBDA Director: Dr. Eric R. Switzer
NASA Official: Dr. Eric R. Switzer
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