Monday, November 2, 2015

Update on BB modes from BICEP/KECK: Dust is looking more likely

Just today the BICEP/KECK group just placed a new manuscript on arxiv with their latest data on BB modes. Included in the new paper is data collected by the KECK telescope at 95 GHz. (The new data is in red in the figure below.)
The gist of the paper is that the new data at 95 GHz finds only very slight (if any) evidence for BB-modes from  tensor-modes (i.e. inflationary-based gravitational waves.) Right now, there's not enough data to rule out dust. The error bars are just too large to say anything conclusively. The point here is that more data at 95 GHz (where there is less signal from dust than at 150 GHz) does not help to confirm the tensor-mode nature of the signal found at 150 GHz. (Note that this does not help or hurt inflation theories in general; it only helps to rule out a few of the theories that predict large values of r. In my opinion, slow-roll inflation with the Higgs field as the slow-roll scalar field for inflation is a pretty strong theory. The question is: what is the scale of inflation? And this new data seems to suggest that the energy scale for inflation is low enough that it will be difficult to experimentally measure tensor-mode gravitational waves over the next decade.)