  We describe an analysis comparing the $p\bar{p}$ elastic cross section as
measured by the D0 Collaboration at a center-of-mass energy of 1.96 TeV to that
in $pp$ collisions as measured by the TOTEM Collaboration at 2.76, 7, 8, and 13
TeV using a model-independent approach. The TOTEM cross sections extrapolated
to a center-of-mass energy of $\sqrt{s} =$ 1.96 TeV are compared with the D0
measurement in the region of the diffractive minimum and the second maximum of
the $pp$ cross section. The two data sets disagree at the 3.4$\sigma$ level and
thus provide evidence for the $t$-channel exchange of a colorless, $C$-odd
gluonic compound, also known as the odderon. We combine these results with a
TOTEM analysis of the same $C$-odd exchange based on the total cross section
and the ratio of the real to imaginary parts of the forward elastic scattering
amplitude in $pp$ scattering. The combined significance of these results is
larger than 5$\sigma$ and is interpreted as the first observation of the
exchange of a colorless, $C$-odd gluonic compound.
