Exotic diboson searches in the $\ell\nu qq$ final state using proton-proton collisions data at $\sqrt{s} = 13\ TeV$ collected with the ATLAS detector.

Analyses searching for diboson resonances are very powerful tools to investigate many beyond the Standard Model scenarios such as extension of the Higgs sector, Heavy Vector triplets ($W^{'}$ and $Z^{'}$) or excited states of Gravitons. These searches exploit the many decay channels of the two bosons allowing to select topologies with varied signal to background ratios and statistics. Among these searches the one looking for $WW$/$WZ$ in the semileptonic final state finds a compromise between the high signal statistics allowed by the high branching ratio of the hadronic decay of the gauge boson while profiting of the good trigger and analysis signature of the lepton, decay product of the second gauge boson. The $WW$/$WZ$ search for TeV scale resonances in the $\ell\nu qq$ channel with $36.1~\ifb$ of data collected with the ATLAS detector at $\sqrt{s} = 13 \TeV$ will be detailed. No significant excess is observed in data with respect to the Standard Model backgrounds. Limits on the production cross section are set for various benchmark scenarios.