Single top partner production in the Higgs to diphoton channel in the Littlest Higgs Model with $T$-parity

TL;DR

This paper studies the potential to detect the single production of the T-even top partner in the Littlest Higgs model with T-parity at the LHC, focusing on the Higgs to diphoton decay channel, and finds it can exclude masses up to 800 GeV.

Contribution

It provides a detailed analysis of the observability of the T-even top partner via single production in the diphoton channel at the LHC, considering current constraints and future collider capabilities.

Findings

T-even top partner mass > 730 GeV is excluded by current data.

Single production process can exclude T_+ masses up to 800 GeV at 14 TeV LHC.

The diphoton channel offers a promising search avenue for the T-even top partner.

Abstract

The top partner as a hallmark of the Littlest Higgs model with $T$-parity (LHT model) has been extensively searched for during the Large Hadron Collider (LHC) Run-1. With the increasing mass limits on the top partner, the single production of the top partner will be dominant over the pair production. Under the constraints from the Higgs data, the electroweak precision observables and $R_b$, we find that the mass of $T$-even top partner ($T_+$) has to be heavier than 730 GeV. Then, we investigate the observability of the single $T$-even top partner production through the process $pp \to T_+ j$ with the sequent decay $T_+ \to th$ in the di-photon channel in the LHT model at the LHC. We find that the mass of $T_+$ can be excluded up to 800 GeV at $2\sigma$ level at 14 TeV LHC with the integrated luminosity ${\cal L}=3$ ab$^{-1}$.