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 gqq¯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 mZZ satisfies the condition mZZ>2mZ. In the region mZZ>300GeV 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.