ATLAS collaboration (2885 authors)Aguilar Saavedra, Juan AntonioAmor Dos Santos, Susana PatriciaAnjos, NunoAraque Espinosa, Juan PedroCastro, Nuno FilipeConde Mui\~no, PatriciaDa Cunha Sargedas De Sousa, Mario JoseFiolhais, MiguelGalhardo, BrunoGomes, AgostinhoGoncalo, RicardoJorge, PedroMachado Miguens, JoanaMaio, AmeliaManeira, JoseOleiro Seabra, Luis FilipeOnofre, Ant\'onioCosta Batalha Pedro, RuteSantos, HelenaSaraiva, JoaoSilva, Jose ManuelTavares Delgado, AdemarVeloso, FilipeWolters, Helmut2019-02-052019-02-052019-01-10http://dx.doi.org/10.1016/j.physletb.2018.09.062http://hdl.handle.net/10400.26/27564This Letter presents a search for new light resonances decaying to pairs of quarks and produced in association with a high- pT photon or jet. The dataset consists of proton–proton collisions with an integrated luminosity of 36.1 fb −1 at a centre-of-mass energy of s=13 TeV recorded by the ATLAS detector at the Large Hadron Collider. Resonance candidates are identified as massive large-radius jets with substructure consistent with a particle decaying into a quark pair. The mass spectrum of the candidates is examined for local excesses above background. No evidence of a new resonance is observed in the data, which are used to exclude the production of a lepto-phobic axial-vector Z′ boson.engjournal article2019-02-05