Investigation of exotic charmonium states in the LHCb experiment

The most recent results of investigations into exotic charmonium states in the LHCb experiment are presented. The quantum numbers of the X (3872) state were measured, a piece of evidence for the decay X (3872)→ ψ (2 S ) γ was obtained, and the existence of the Z (4430) − state was confirmed. The analyses that led to these results were based on data accumulated by the LHCb detector in proton–proton collisions at the c.m. energies of 7 and 8 TeV. The data sample used corresponded to integrated luminosities between 1 and 3 fb −1 .