Investigation of interference effects in resonant and non-resonant Beyond the Standard Model Higgs Pair Production at ATLAS*

Searching for Higgs pair production, in events with two b-jets and two τ-leptons, the Standard Model predicts non-resonant HH production below the sensitivity of the currently available LHC data set. Significant non-resonant and resonant enhancements to the HH cross section are predicted in many Beyond-the-Standard-Model theories, including a Heavy Higgs boson decaying to two 125 GeV mass Higgs bosons.

Experimentalists have been using the narrow width approximation for the heavy Higgs resonance, ignoring the possible influence of higher widths. Is it safe to assume we can use the narrow approximation, or could variable widths have a significant influence on the interference between the heavy Higgs and the Standard Model Higgs?

We investigate Higgs pair production in the final state with two b-jets and two τ-leptons using MadGraph at the Parton level. The studies include a range of point masses for the heavy Higgs from 300 to 2000 GeV. Each point mass is generated at variable widths of the heavy Higgs resonance.

Interference between the non-resonant and heavy Higgs resonant production were found to be dependent on mass point and width. Particular masses interference is greatest at particular widths. Thus, we should be testing at all widths, especially with particular point masses.