Composite 2-Higgs Doublet Model: Strong Effects on Higgs Pair Production

TL;DR

This paper explores how a Composite 2-Higgs Doublet Model can significantly alter Higgs pair production at the LHC through resonant and non-resonant effects, involving new heavy quarks and modified couplings.

Contribution

It introduces the impact of compositeness effects in a Composite 2-Higgs Doublet Model on Higgs pair production, including new interference phenomena and shape distortions.

Findings

Resonant distortions of scalar decay shapes due to interference effects.

Non-resonant modifications with a local maximum at twice the heavy quark mass.

Quantitative bounds considering theoretical and experimental constraints.

Abstract

We show how effects of compositeness emerging in a Composite 2-Higgs Doublet Model can enter Standard Model (SM)-like Higgs pair production at the Large Hadron Collider in both resonant and non-resonant mode. Such effects can arise from modified trilinear Higgs self-couplings and top-Yukawa couplings as well as from loops of new heavy quarks and additional quartic Higgs-fermion interactions. In the resonant case, significant distortions of the Breit- Wigner shape of a new scalar state decaying into the two SM-like Higgs states may occur due to interference effects amongst not only the SM-like diagrams but also those involving the new heavy quarks. In the non-resonant case, a modification of the underlying line-shape and a local maximum at twice a new heavy quark mass appear simultaneously. We quantify these effects by taking into account the relevant theoretical and latest experimental bounds.