LHC Phenomenology of Composite 2-Higgs Doublet Models

TL;DR

This paper explores the phenomenology of Composite 2-Higgs Doublet Models (C2HDMs), highlighting how their Yukawa coupling structures lead to distinct collider signatures compared to elementary models, aiding experimental differentiation.

Contribution

It introduces a specific construction of C2HDMs based on $SO(6)$ symmetry breaking and compares their phenomenology with elementary models, emphasizing differences in Higgs couplings and collider signatures.

Findings

Significant differences in Yukawa coupling structures between C2HDM and E2HDM.

Distinct production and decay patterns of extra Higgs bosons at the LHC.

Potential to distinguish models through collider measurements of Higgs properties.

Abstract

We investigate the phenomenology of Composite 2-Higgs Doublet Models (C2HDMs) of various Yukawa types based on the global symmetry breaking $SO(6)\to SO(4)\times SO(2)$. The kinetic term and the Yukawa Lagrangian are constructed in terms of the pseudo Nambu-Goldstone Boson (pNGB) matrix and a 6-plet of fermions under $SO(6)$. The scalar potential is assumed to be the same as that of the Elementary 2-Higgs Doublet Model (E2HDM) with a softly-broken discrete $Z_2$ symmetry. We then discuss the phenomenological differences between the E2HDM and C2HDM by focusing on the deviations from Standard Model (SM) couplings of the discovered Higgs state ($h$) as well as on the production cross sections and Branching Ratios (BRs) at the Large Hadron Collider (LHC) of extra Higgs bosons. We find that, even if the same deviation in the $hVV$ ($V=W,Z$) coupling is assumed in both scenarios, there appear significant differences between E2HDM and C2HDM from the structure of the Yukawa couplings, so that production and decay features of extra Higgs bosons can be used to distinguish between the two scenarios.