# Electroweak production of Higgs boson pairs in 2HDMs

## TL;DR

This paper demonstrates that in certain 2HDMs, electroweak production of Higgs pairs can surpass QCD processes, especially when the sum of light Higgs masses is below the Z-boson mass, challenging prior assumptions.

## Contribution

It reveals that electroweak Higgs pair production can dominate over QCD in specific 2HDM parameter regions, highlighting an overlooked production mechanism.

## Key findings

- EW production can dominate over QCD when Higgs masses sum to less than Z mass
- Electroweak processes are significant in certain 2HDM scenarios
- Challenging the assumption that EW contributions are always subleading

## Abstract

One of the main features of a Two-Higgs Doublet Model (2HDM) is the presence of two additional neutral Higgs states, besides the one mimicking the ~125 GeV state observed at the LHC. The three Higgs bosons of a 2HDM can be produced at the LHC either singly via gluon fusion or in pairs with each other. When analyzing their pair production, the emphasis is laid on gluon-initiated processes, and the electroweak (EW) production is generally not treated on the same footing, assuming its contribution to be highly subleading. We show here that when the sum of the masses of the lightest scalar and pseudoscalar Higgs bosons in the Type-I 2HDM is smaller than the Z-boson mass, their EW pair production can dominate over QCD pair production by orders of magnitude.