  WW/ZZ interference for Higgs signal and continuum background as well as
signal-background interference is studied for same-flavour l anti-nu_l anti-l
nu_l final states produced in gluon-gluon scattering at the LHC for light and
heavy Higgs masses with minimal and realistic experimental selection cuts. For
the signal cross section, we find WW/ZZ interference effects of O(5%) at M_H =
126 GeV. For M_H >= 200 GeV, we find that WW/ZZ interference is negligible. For
the gg continuum background, we also find that WW/ZZ interference is
negligible. As general rule, we conclude that non-negligible WW/ZZ interference
effects occur only if at least one weak boson of the pair is dominantly
off-shell due to kinematic constraints. The subdominant weak boson pair
contribution induces a correction to the signal-background interference, which
is at the few percentage point level before search selection cuts. Optimised
selection cuts for M_H >~ 600 GeV are suggested.
