With the LHC proton-proton collision data at an energy of 13 TeV recorded by the ATLAS detector, this analysis searches for the production of a new particle W' with a yet-to-be-probed mass in the top quark plus bottom quark decay channel. The boosted and hadronically decaying top-quark is reconstructed as a large-radius jet and identified using jet substructures. A secondary-vertex finding algorithm identifies small-radius jets originating from a bottom quark. After the identification stage, the main background events come from the Quantum Chromodynamical production of multi-jet, which is estimated by a data-driven approach. The statistical data analysis searches for a resonant peak in the invariant mass distribution of the system with a jet associated with the top quark and another with the bottom quark. The consistency between data and the background prediction is found in the invariant mass range between 1 TeV to 7 TeV, and an upper limit at the 95% confidence level is set on the production cross-section times branching ratio for a W' boson with right-handed chirality decaying to a top quark and a bottom quark. A lower limit on the W' mass is set at 4.4 TeV accordingly.
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