Latest BICEP2/Keck Array/Planck Results on Primordial Gravitational Waves

A new joint analysis of BICEP2/Keck Array and Planck data fits the CMBR polarization measurements carried out by these experiments to an improved model of galactic dust and a possible contribution from primordial gravitational waves generated by inflation. This new analysis yields a new upper limit for the contribution from primordial gravitational waves but no longer disfavours a zero contribution at high statistical significance. The authors conclude that to better constrain, or to definitively detect, primordial inflationary gravitational waves will therefore require additional data. Hence for the moment the search for primordial gravitational waves continues, although the authors note that many other experiments to measure CMBR polarization are currently underway.