Search for $W' \rightarrow t\bar{b}$ in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 8 TeV with the ATLAS detector

A search for $W'$ bosons is performed with the ATLAS detector at the LHC in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 8 TeV, using a dataset corresponding to an integrated luminosity of 14.3 $fb^{-1}$. This analysis searches for $W'$ bosons in the $W' \rightarrow t\bar{b} \rightarrow l \nu b\bar{b}$ decay channel in final states with electrons or muons, using a multivariate method based on boosted decision trees. The search range covers $W'$-boson masses between 0.5 and 3.0 TeV, with right-handed or left-handed $W'$-boson chiralities. No significant deviation from the Standard Model expectation is observed and upper limits are set on the $W' \rightarrow t\bar{b}$ cross-section times branching ratio and on the $W'$-boson effective couplings as a function of the $W'$-boson mass, using the CLs procedure. For a left-handed (right-handed) $W'$ boson, masses below 1.74 (1.84) TeV are excluded at 95% confidence level.