Production and spectroscopy of quarkonia states at the ATLAS experiment

This presentation will cover ATLAS results in the domain of charmonium production, including J/psi, psi(2s) and chi_c states. The analyses discussed include double-differential production cross-section measurements of the J/psi, psi(2S) and P-wave charmonium states chi_cJ, extending upon previous measurements in precision and kinematic reach. Prompt and non-prompt modes are distinguished, as well as J/psi vs psi(2s) and the contribution to J/psi production from chi_c feed-down. Alongside the latter analysis, a competitive measurement of the branching fraction B± --> chi_c1 + K± was also performed. Results of the measurements are compared with the latest theoretical predictions from a variety of theoretical approaches.