Abstract In this paper, a collider signature of a heavy Higgs boson at 14 TeV HL-LHC is studied, where
the heavy Higgs boson decays into a pair of standard model Higgs boson, which further decays to
bbZZ state and subsequently to bbℓ+ℓ−νℓνℓ final state. To study this, we consider singlet scalar
extension of the standard model and select the parameter space and mass of the heavy Higgs such
that it prefers a strong first order electroweak phase transition. The study is done following the
bbZZ analysis of CMS Collaboration and further using parameterized machine learning for final
discrimination which simplifies the training process along with an improved discrimination between
signal and background over the range of benchmark points. Despite the lower branching fraction,
this channel can be a potential probe of the electroweak phase transition with the data sets collected
by the CMS and ATLAS experiments at the 14 TeV HL-LHC with 3 ab−1 of integrated luminosity
and a production of resonant di-Higgs signal can be potentially discovered.