# Search for single production of vector-like top partners at the Large Hadron Electron Collider

## TL;DR

This paper proposes a search strategy for single production of vector-like top partners at the LHeC, analyzing decay channels and estimating exclusion limits on couplings for different masses and luminosities.

## Contribution

It introduces a novel search approach for vector-like top partners at the LHeC, focusing on specific decay channels and providing sensitivity estimates for various parameters.

## Key findings

- Potential to exclude $TWb$ couplings at 3σ level for masses up to 1 TeV.
- Analysis of decay channels $T o Wb$ and $T o th$ at the LHeC.
- Sensitivity estimates for different integrated luminosities.

## Abstract

The new vector-like top partners with charge $2/3$ are a typical feature of many new physics models beyond the Standard Model (SM). We propose a search strategy for single production of top partners $T$ focusing on both the $T\to Wb$ and $T\to th$ decay channels at the Large Hadron Electron Collider (LHeC). Our analysis is based on a simplified model in which the top partner is an $SU(2)$ singlet, with couplings only to the third generation of SM quarks. We study the observability of the single $T$ through the processes $e^{+}p \to T(\to bW^{+})\bar{\nu}_{e}\to b\ell^{+}+ \not E_T^{miss}$ and $e^{+}p \to T(\to th)\bar{\nu}_{e}\to t(\to jj'b)h(\to b\bar{b}) \not E_T^{miss}$ at the LHeC with the proposed 140 GeV electron beam (with $80\%$ polarization) and 7 TeV proton beam. For three typical $T$-quark masses (800, 900 and 1000 GeV), the $3\sigma$ exclusion limits on the $TWb$ coupling are respectively presented for various values of the integrated luminosity.