Observability of 2HDM neutral Higgs bosons with different masses at future $e^+e^-$ linear colliders

TL;DR

This paper investigates the potential to observe heavy neutral Higgs bosons in the 2HDM at future 1 TeV linear colliders, demonstrating that both can be detected with high significance and measured accurately.

Contribution

It provides a detailed simulation study showing the observability of heavy neutral Higgs bosons in the 2HDM at future linear colliders with specific benchmark points.

Findings

Both Higgs bosons are observable with >5σ significance.

Masses can be measured accurately at 500 fb^{-1} luminosity.

Simulation confirms detectability in the specified parameter space.

Abstract

Assuming two Higgs doublet model (2HDM) at SM-like scenario as the theoretical framework, this study addresses the question of observability of heavy neutral CP-even and CP-odd Higgs bosons $H$ and $A$ at a linear collider operating at $\sqrt{s}=1$ TeV. The signal production channel is $e^- e^+ \rightarrow A H \rightarrow ZHH$ with subsequent leptonic decay of the $Z$ boson and Higgs bosons decays into $b$ quark pairs. Therefore, to be specific, type-I 2HDM is used to allow dominant Higgs boson decay to b-quark pairs below the top quark pair production threshold. Two benchmark points with mass ranges $150\leq m_H\leq 200$ and $250\leq m_A\leq 300$ are simulated. The relevant energy and momentum smearing is applied and appropriate selection cuts are imposed to enrich signal events. Results indicate that both Higgs bosons are observable with signals exceeding $5\sigma$ significance with possibility of mass measurement at the integrated luminosity of 500 $fb^{-1}$.