Anomalous $H\to ZZ\to 4\mathrm{\ell }$ decay and its interference effects at the LHC

We calculate the spinor helicity amplitudes of anomalous $H\to ZZ\to 4\mathrm{\ell }$ decay. After embedding these analytic formulas into the $\mathtt{\text{MCFM}}$ package, we study the interference effects between the anomalous $gg\to H\to ZZ \to 4\ell$ process and the SM processes, which are indispensable in the Higgs off-shell region. Subsequently, the constraints on the anomalous couplings are estimated using LHC experimental data.