“…The latter are heavy spin 1/2 particles that transform as triplets under colour and whose left-and right-handed couplings have the same Quantum Chromo-Dynamics (QCD) and Electro-Weak (EW) quantum numbers. These states are predicted by various theoretical models (composite Higgs models [5][6][7][8][9][10][11][12], models with extra dimensions, little Higgs models [13,14], models with gauging of the flavour group [15][16][17][18], non-minimal supersymmetric extensions of the Standard Model (SM) [19][20][21][22][23][24], Grand Unified Theories [25,26]) and can be observed in a large number of final states, depending on how they interact with SM particles (see for example [27-29, 32, 33] for general reviews). Usually experimental searches for vector-like quarks adopt a phenomenological approach, assuming that only one new Q V state is present beyond the SM and, in order to be as model independent as possible, searches usually consider QCD pair production, although very recently single production has also been explored [35].…”