Higgs EFT for 2HDM and beyond

TL;DR

This paper evaluates the use of Standard Model Effective Field Theory to interpret Higgs data within the two-Higgs-doublet Model, analyzing the validity of the EFT approach and identifying coupling patterns that improve data fit.

Contribution

It clarifies the conditions under which the EFT accurately reflects the 2HDM and explores how to modify Higgs couplings to better fit experimental data.

Findings

EFT constraints can be translated into 2HDM parameters under certain conditions.

Increasing top Yukawa and decreasing bottom Yukawa couplings improves Higgs data fit.

Introducing new colored particles in 2HDM can realize the coupling modifications.

Abstract

We discuss the validity of the Standard Model Effective Field Theory (SM EFT) as the low-energy effective theory for the two-Higgs-doublet Model (2HDM). Using the up-to-date Higgs signal strength measurements at the LHC, one can obtain a likelihood function for the Wilson coefficients of dimension-6 operators in the EFT Lagrangian. Given the matching between the 2HDM and the EFT, the constraints on the Wilson coefficients can be translated into constraints on the parameters of the 2HDM Lagrangian. We discuss under which conditions such a procedure correctly reproduces the true limits on the 2HDM. Finally, we employ the SM EFT to identify the pattern of the Higgs boson couplings that are needed to improve the fit to the current Higgs data. To this end, one needs, simultaneously, to increase the top Yukawa coupling, decrease the bottom Yukawa coupling, and induce a new contact interaction of the Higgs boson with gluons. We comment on how these modifications can be realized in the 2HDM extended by new colored particles.