Recent Experiments at Fermi Lab seem to support earlier work done at CERN
which suggest that a three sigma deviation of the Weak mixing angle from the
predicted standard model value is being observed. ( Actually Sin^2[theta_w] )
This is viewed as a significant but not conclusive deviation.
The experiments consist of producing large numbers of neutrinos and anti
neutrinos and observing the ratio of neutral current interactions to charged
current interactions. Current data indicates that the neutral current
interactions are less than expected. Some possible explanations for this is
the existence of Z prime bosons or leptoquark bosons predicted by GUTs.
If this data holds up than this may be the first indication of physics
beyond the standard model observed in an accelerator.