Alignment and Enhanced Multi-Higgs Production

Abstract

Contrary to conventional expectations, we identify a class of extended scalar-sector scenarios in which final states with two, three, or four Higgs bosons constitute the leading discovery channels for new physics at the LHC. In these scenarios, higher-dimensional interactions, together with suppressed Higgs-scalar mixing near the alignment limit, reorganize the decay patterns of new scalar states, suppressing conventional modes while enhancing multi-Higgs final states. We illustrate the emergence of dominant triple- and quadruple-Higgs signatures in two representative realizations: a single-scalar extension of the Standard Model, where higher-dimensional operators suppress conventional two-body decays while preserving couplings to higher-multiplicity Higgs final states; and a two-singlet scenario, where similar signatures arise through cascade decays with a simpler operator structure. In both cases, the new scalar states can be produced via gluon fusion, yielding potentially observable rates for multi-Higgs production at the LHC. Although both realizations lead to identical final states, they exhibit distinct kinematic features reflecting their underlying topologies, providing a direct handle on the dynamics.