Quark-lepton effective contact interactions at large scales can be pro
bed by the shape of the isolated dilepton invariant-mass distribution
at LHC. After removing the ttBAR-background by a suitable invariant-ma
ss cut m0, we study the improved statistical LAMBDA-bounds thus obtain
able in terms of the fermionic current chirality, beam luminosity, cut
m0, and binwidth DELTAm. The limitations imposed on these bounds by s
ystematic uncertainties are also examined.