Confirmation of the detection of B-modes in the Planck polarization maps
  One of the main problems for extracting the Cosmic Microwave Background (CMB)
from submm/mm observations is to correct for the Galactic components, mainly
synchrotron, free - free and thermal dust emission with the required accuracy.
Through a series of papers, it has been demonstrated that this task can be
fulfilled by means of simple neural networks with high confidence. The main
purpose of this paper is to demonstrate that the CMB BB power spectrum detected
in the Planck 2015 polarization maps is present in the improved Planck 2017
maps with higher signal-to-noise ratio. Two features have been detected in the
EB power spectrum in the new data set, both with S/N $\sim$4 . The origin of
these features is most likely leakage from E to B with a level of about 1 per
cent. This leakage gives no significant contribution to the detected BB power
spectrum. The TB power spectrum is consistent with a zero signal. Altogether,
the BB power spectrum is not consistent with the 'canonical' tensor-to-scalar
models combined with gravitational lensing spectra. These results will give
additional strong arguments for support to the proposed polarization satellite
projects to follow up on the Planck mission .
