  A joint analysis of data collected by the Planck and BICEP2+Keck teams has
previously given $r = 0.09^{+0.06}_{-0.04}$ for BICEP2 and $r =
0.02^{+0.04}_{-0.02}$ for Keck. Analyzing BICEP2 using its published noise
estimate, we had earlier (Colley & Gott 2015) found $r = 0.09 \pm 0.04$,
agreeing with the final joint results for BICEP2. With the Keck data now
available, we have done something the joint analysis did not: a correlation
study of the BICEP2 vs. Keck B-mode maps. Knowing the correlation coefficient
between the two and their amplitudes allows us to determine the noise in each
map (which we check using the E-modes). We find the noise power in the BICEP2
map to be twice the original BICEP2 published estimate, explaining the
anomalously high $r$ value obtained by BICEP2. We now find $r = 0.004 \pm 0.04$
for BICEP2 and $r = -0.01 \pm 0.04$ for Keck. Since $r \ge 0$ by definition,
this implies a maximum likelihood value of $r = 0$, or no evidence for
gravitational waves. Starobinsky Inflation ($r = 0.0036$) is not ruled out,
however. Krauss & Wilzcek (2014) have already argued that "measurement of
polarization of the CMB due to a long-wavelength stochastic background of
gravitational waves from Inflation in the early Universe would firmly establish
the quantization of gravity," and, therefore, the existence of gravitons. We
argue it would also constitute a detection of gravitational Hawking radiation
(explicitly from the causal horizons due to Inflation).
