  Many extensions of the Standard Model (SM) predict new neutral vector bosons
at energies accessible by the Large Hadron Collider (LHC). We study an
extension of the SM with new chiral fermions subject to non-trivial anomaly
cancellations. If the new fermions have SM charges, but are too heavy to be
created at LHC, and the SM fermions are not charged under the extra gauge
field, one would expect that this new sector remains completely invisible at
LHC. We show, however, that a non-trivial anomaly cancellation between the new
heavy fermions may give rise to observable effects in the gauge boson sector
that can be seen at the LHC and distinguished from backgrounds.
