Improved limits on the tensor-to-scalar ratio using BICEP and Planck [CEA]

http://arxiv.org/abs/2112.07961


We present constraints on the tensor-to-scalar ratio r using a combination of BICEP/Keck 2018 and Planck PR4 data allowing us to fit for r consistently with the six parameters of the $\Lambda$CDM model without fixing any of them. In particular, we are able to derive a constraint on the reionization optical depth $\tau$ and thus propagate its uncertainty onto the posterior distribution for r. While Planck sensitivity to r is no longer comparable with ground-based measurements, combining Planck with BK18 and BAO gives results consistent with r = 0 and tightens the constraint to r < 0.032.

Read this paper on arXiv…

M. Tristram, A. Banday, K. Górski, et. al.
Thu, 16 Dec 21
65/83

Comments: 6 pages, 6 figures, submitted to PRL