Maximal value for trilinear Higgs coupling in a 3-3-1 EFT

TL;DR

This paper derives an effective field theory for a class of BSM models based on the 3-3-1 gauge group, showing that the maximal trilinear Higgs coupling can be over four times larger than the Standard Model prediction, with potential experimental testability.

Contribution

It provides a consistent EFT derivation for 3-3-1 models, revealing the possibility of significantly enhanced trilinear Higgs couplings beyond the SM.

Findings

Maximum trilinear Higgs coupling exceeds four times the SM value.

Large couplings are only achievable in out-of-alignment scenarios.

Potential for testing these large couplings at future colliders.

Abstract

Recent efforts, both theoretical and experimental, have increasingly focused on the scalar potential of the Standard Model, with a highlight on the trilinear Higgs coupling. This parameter has long been recognized for its potential to test Beyond-Standard-Model (BSM) theories and its significance in understanding early cosmological dynamics. In order to broadly map BSM scenarios, a powerful tool is to devise its effective field theory (EFT) version for low-energies. In this work, we obtain a consistent EFT for a class of models based on the gauge group $SU(3)_c\times SU(3)_L\times U(1)_Y$. After properly matching the UV-complete theory at one-loop, we show that the EFT is a Two-Higgs-Doublet Model (2HDM), where some of the quartic couplings are naturally small. By imposing bounds from electroweak precision observables, collider, flavor, as well as theoretical considerations, we obtain that the maximum value of the trilinear Higgs coupling is more than four times larger than the SM prediction, potentially testable at the LHC Hi-Lumi upgrade and other future colliders. Moreover, we find that such large values are only attainable if one considers an out-of-alignment scenario, even if the deviation is very small.