  Collisions of composite particles impose an arbitrary boost in the
longitudinal direction on a given event. This implies that the centre-of-mass
frame at hadron colliders is undetermined for processes with missing energy in
the final state. This motivates the modification of the Fox-Wolfram moments
such that the moments for a given event are identical when viewed in the lab or
centre-of-mass frame of the beam. The resulting moments are invariant under
rotations in the plane transverse to the beam and boosts parallel to the beam.
These moments are then used to demonstrate improved signal separation in the
channel where the Higgs decays to two b-quarks while being produced in
association with a vector boson.
