Constraining the Higgs boson width with ZZ production at the LHC

Understand

We point out that existing measurements of $pp \to ZZ$ cross-section at the LHC in a broad range of ZZ invariant masses allow one to derive a model-independent upper bound on the Higgs boson width, thanks to strongly enhanced off-shell Higgs contribution.

• Using CMS data and considering events in the interval of ZZ invariant masses from 100 to 800 GeV, we find $\Gamma_H \le 38.8 \times \Gamma_H^{SM} \approx 163$ MeV, at the $95\%$ confidence level.
• Restricting ZZ invariant masses to $M_{ZZ} \ge 300$ GeV range, we estimate that this bound can be improved to $\Gamma_H \le 21 \times \Gamma_H^{SM} \approx 88$ MeV.
• Under the assumption that all couplings of the Higgs boson to Standard Model particles scale in a universal way, our result can be translated into an upper limit on the branching fraction of the Higgs boson decay to invisible final states.