Searches for Extra Higgs Bosons using $t\bar{t}+$Higgs{{$(\to b\bar b)$}} Events within 2HDMs: Direct versus Indirect Probes

TL;DR

This paper proposes a novel method to detect and characterize additional Higgs bosons in 2HDMs at the LHC by analyzing the kinematic features of the $tar t$ system, offering advantages over traditional decay reconstruction techniques.

Contribution

It introduces a new approach for discovering and studying extra Higgs states via inclusive $tar t$ production, improving over existing decay-based methods.

Findings

The method can extract Higgs masses from $tar t$ kinematics.

It can determine the CP properties of Higgs states.

Sensitivity is demonstrated for a Composite 2HDM scenario.

Abstract

We study the possibility of establishing the production of additional Higgs states in the process $gg,q\bar q\to t\bar t \Phi$, where $\Phi$ = $H_{2,3}$, with $H_2$ being CP-even and $H_3$ being CP-odd, at the Large Hadron Collider (LHC), by solely exploiting the kinematic features of the reconstructed $t\bar t$ system. We adopt as reference theoretical framework a generic CP-Conserving 2-Higgs Doublet Model (2HDM), which also accommodate a Standard Model (SM)-like Higgs state $H_1$. We show that the masses $m_{H_{2,3}}$ exhibit clear correlations with the $t\bar{t}$ system properties and could, in principle, be extracted from these. Moreover, the CP properties of the $H_{2,3}$ states can be determined, even when both states are produced simultaneously. We then compare the results produced using this method with those obtained from a full kinematic reconstruction of the $H_{2,3}$ decays in the most studied $b\bar b$ channel (we take $m_{H_{2,3}}< 2m_t$), thus proving the superiority of the approach here proposed. This paves the way to both the discovery and characterization of additional Higgs states produced {\sl inclusively} in association with top-antitop quark pairs, thereby dispensing of the complications intrinsic to the {\sl exclusive} reconstruction of such states from their decay products. We test this by establishing the sensitivity of our approach in the case of a Composite 2HDM (C2HDM), describing the Higges as pseudo-Nambu Goldstone Bosons (pNGBs) and naturally predicting Higgs mass spectra in the range of sensitivity of the described analysis.