Phenomenology of 2HDM with VLQs

TL;DR

This paper explores a 2HDM with VLQs to explain LHC data on Higgs boson production and decay, performing a global fit and analyzing phenomenological implications, including potential explanations for observed anomalies.

Contribution

It introduces a viable 2HDM with VLQs that can account for LHC Higgs data and provides a comprehensive phenomenological analysis of the model's features and experimental constraints.

Findings

VLQ with charge 2/3 explains LHC Higgs data for 350 GeV to 1.5 TeV masses.

Model fits within 2σ of LHC measurements after including constraints.

Analysis of T decay channels highlights promising experimental signatures.

Abstract

In this paper, we examine the consistency of the Large Hadron Collider (LHC) data collected during Run 1 and 2 by the ATLAS and CMS experiments with the predictions of a 2-Higgs Doublet Model (2HDM) embedding Vector-Like Quarks (VLQs) for $pp \to H,A$ production and $H,A\to\gamma\gamma$ decay mechanisms, respectively, of (nearly) degenerate CP-even ($H$) and CP-odd ($A$) Higgs bosons. We show that a scenario containing one single VLQ with Electro-Magnetic (EM) charge $2/3$ can explain the above ATLAS and CMS data for masses in the region 350 GeV $\leq m_{\rm VLQ}\leq 1.5$ TeV or so, depending on $\tan\beta$, and for several values of the mixing angle between the top quark ($t$) and its VLQ counterpart ($T$).We then perform a global fit onto the model by including all relevant experimental as well as theoretical constraints. The surviving samples of our analysis are discussed within 2$\sigma$ of the LHC measurements. Additionally, we also comment on the recent anomalous result reported by CMS using Run 2 data on the associated Standard Model (SM) Higgs boson production with top quark pairs $pp\to t\bar th$ with an observed significance of 3.3$\sigma$. Other than these specific examples, we also present a phenomenological analysis of the main features of the model, including the most promising $T$ decay channels.