The Flavour-Changing Neutral Currents Decay t-->Hq at ATLAS Experiment

TL;DR

This study assesses the ATLAS experiment's potential to detect rare top-quark decays via flavor-changing neutral currents, focusing on the decay t --> Hq and its observability at 14 TeV with specific Higgs masses.

Contribution

It provides a detailed simulation-based analysis of the ATLAS sensitivity to the t --> Hq decay mode, including background analysis and discovery potential at 14 TeV.

Findings

Potential to discover t --> Hq decay with branching ratios as low as 2.0x10^{-3} for m_H=150 GeV.

Analysis shows the significance of specific decay channels at 100 fb^{-1} luminosity.

Background processes like ttbar, ttbar H, WZ, and WH were thoroughly studied.

Abstract

The sensitivity of the ATLAS experiment to the top-quark rare decay via flavour-changing neutral currents t --> Hq (q represents c and u quarks) has been studied at sqrt{s} = 14 TeV in the decay mode of ttbar --> HqWb --> WW*q,Wb -->l \nu l \nu j, l^{\pm} \nu b, (l=e, \mu). The Standard Model backgrounds ttbar, ttbar H, WZ and WH have been analysed. The signal and backgrounds were generated via PYTHIA 5.7 and simulated and analysed using ATLFAST 2.51. A branching ratio for t --> Hq -->WW*q as low as 2.0x10^{-3} for m_H=150 GeV and 2.1x10^{-3} for m_H=160 GeV could be discovered at the 5 \sigma level with an integrated luminosity of 100 fb^{-1}.