Abstract
The _(b)(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider at sqrt[s] = 7__TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4__fb(-1), these states are reconstructed through their radiative decays to _(1S,2S) with _ _ _+ _-. In addition to the mass peaks corresponding to the decay modes _(b)(1P,2P) _ _(1S)_, a new structure centered at a mass of 10.530 ± 0.005(stat) ± 0.009(syst)__GeV is also observed, in both the _(1S)_ and _(2S)_ decay modes. This structure is interpreted as the _(b)(3P) system.