ATLAS collaboration (2891 authors)Aguilar-Saavedra, Juan AntonioAmor Dos Santos, Susana PatriciaAnjos, NunoAraque, Juan PedroCantrill, RobertCarvalho, JoãoCastro, Nuno FilipeConde Muiño, PatriciaDa Cunha Sargedas De Sousa, Mario JoseDo Valle Wemans, AndréFiolhais, MiguelGalhardo, BrunoGomes, AgostinhoGonçalo, RicardoJorge, PedroLopes, LourencoMachado Miguens, JoanaMaio, AméliaManeira, JoséMarques, CarlosOnofre, AntónioPalma, AlbertoPedro, RutePina, João AntonioPinto, BelmiroSantos, HelenaSaraiva, JoãoSilva, JoséTavares Delgado, AdemarVeloso, FilipeWolters, Helmut2019-02-042019-02-042015-04-24http://dx.doi.org/10.1140/epjc/s10052-015-3372-2http://hdl.handle.net/10400.26/26658A search for a massive $W'$ gauge boson decaying to a top quark and a bottom quark is performed with the ATLAS detector in $pp$ collisions at the LHC. The dataset was taken at a centre-of-mass energy of $\sqrt{s} = 8{\mathrm {\ TeV}}$ and corresponds to $20.3\,\text{ fb }^{-1}$ of integrated luminosity. This analysis is done in the hadronic decay mode of the top quark, where novel jet substructure techniques are used to identify jets from high-momentum top quarks. This allows for a search for high-mass $W'$ bosons in the range 1.5–3.0  ${\mathrm {\ TeV}}$ . $b$ -tagging is used to identify jets originating from $b$ -quarks. The data are consistent with Standard Model background-only expectations, and upper limits at 95 % confidence level are set on the $W'\rightarrow tb$ cross section times branching ratio ranging from $0.16\,\mathrm {pb}$ to $0.33\,\mathrm {pb}$ for left-handed $W'$ bosons, and ranging from $0.10\,\mathrm {pb}$ to $0.21\,\mathrm {pb}$ for $W'$ bosons with purely right-handed couplings. Upper limits at 95 % confidence level are set on the $W'$ -boson coupling to $tb$ as a function of the $W'$ mass using an effective field theory approach, which is independent of details of particular models predicting a $W'$ boson.engjournal article2019-02-04