# Resonant Higgs pair production as a probe of stop at the LHC

## TL;DR

This paper explores how resonant Higgs pair production via stoponium decay at the LHC can be used to detect or constrain top squarks, especially in regions where traditional decay channels are suppressed.

## Contribution

It introduces a novel approach using stoponium resonance signals, particularly Higgs pair decay modes, to probe stop properties at the LHC beyond existing methods.

## Key findings

- Strong bounds on stop mass up to 290 GeV in certain mixing regions.
- Potential to probe large stop mixing regions with 3000 fb^{-1} luminosity.
- Significant parameter space coverage at 2σ significance level.

## Abstract

Searching for top squark (stop) is a crucial task of the LHC. When the flavor conserving two body decays of the stop are kinematically forbidden, the stops produced near the threshold will live long enough to form bound states which subsequently decay through annihilation into the Standard Model (SM) final states. In the region of stop mixing angle $\theta_{\tilde{t}} \to 0$ or $\pi/2$, we note that the LHC-13 TeV diphoton resonance data can give a strong bound on the spin-$0$ stoponium ($\eta_{\tilde{t}}$) and exclude the constituent stop mass $m_{\tilde{t}}$ up to about 290 GeV. While in the large stop mixing region, the stoponium will dominantly decay to the Higgs pair. By analyzing the process $pp \to \eta_{\tilde{t}} \to h (\to b\bar{b} )h (\to \tau^+\tau^-)$, we find that a large portion of the parameter space on the $m_{\tilde{t}_1}$ - $\theta_{\tilde{t}}$ plane can be probed at $2\sigma$ significance level at the LHC with the luminosity ${\cal L}=3000$ fb$^{-1}$.