Probing the Anomalous FCNC tqgamma Couplings at Large Hadron electron Collider

TL;DR

This paper explores the potential of the Large Hadron Electron Collider (LHeC) to detect anomalous FCNC interactions of the top quark via specific collision processes, providing bounds on couplings and comparing sensitivities to previous experiments.

Contribution

It introduces a detailed analysis of FCNC top quark couplings at LHeC, including cross section calculations, background analysis, and sensitivity estimates, which are novel for this collider setup.

Findings

Upper bounds on FCNC couplings of order 10^{-2} at 100 fb^{-1} luminosity.

Enhanced sensitivity to $\lambda_{c}$ compared to HERA.

Methodology for distinguishing signal from background using invariant mass distributions.

Abstract

We investigate the anomalous flavour changing neutral current (FCNC) interactions of top quark through the process $e^{-}p\to e^{-}W^{\pm}q+X$. We calculate the signal and background cross sections in electron proton collisions at Large Hadron electron Collider (LHeC) with a 7 TeV proton beam from the LHC and a new 60 GeV electron beam from energy recovery linac (ERL). We study the relevant background processes including one electron and three jets in the final state. The distributions of the invariant mass of two jets and an additional jet tagged as $b$-jet are used to account signal and background events after the analysis cuts. We find upper bounds on anomalous FCNC couplings $\lambda$ of the order of $10^{-2}$ at LHeC for a luminosity projection of $100$ fb$^{-1}$ together with the fast simulation of detector effects. As a matter of interest, we analyze the sensitivity to the couplings $(\lambda_{u},\lambda_{c})$ and find an enhanced sensitivity to $\lambda_{c}$ at the LHeC when compared to the results from the HERA.