Interference effects for Higgs boson mediated Z-pair plus jet production

We study interference effects in the production channel ZZ + jet, in particular focusing on the role of the Higgs boson. This production channel receives contributions both from Higgs boson mediated diagrams via the decay H -> ZZ (signal diagrams), as well as from diagrams where the Z bosons couple directly to a quark loop (background diagrams). We consider the partonic processes gggZZ and gq (q) over bar ZZ in which interference between signal and background diagrams first occurs. Since interference is primarily an off-resonant effect for the Higgs boson, we treat the Z bosons as on shell. Thus our analysis is limited to the region above threshold, where the invariant mass of the Z-pair m(ZZ) satisfies the condition m(ZZ) > 2m(Z). In the region m(ZZ) > 300 GeV we find that the interference in the ZZ + jet channel is qualitatively similar to interference in the inclusive ZZ channel. Moreover, the rates are sufficient to study these effects at the LHC once jet-binned data become available.