Measurement of ? c1 and ? c2 production with sv = 7 TeV pp collisions at ATLAS

The prompt and non-prompt production cross-sections for the ? c1 and ? c2 charmonium states are measured in pp collisions at sv = 7 TeV with the ATLAS detector at the LHC using 4.5 fb-1 of integrated luminosity. The ? c states are reconstructed through the radiative decay ? c ? J/?? (with J/? ? µ + µ -) where photons are reconstructed from ? ? e + e - conversions. The production rate of the ? c2 state relative to the ? c1 state is measured for prompt and non-prompt ? c as a function of J/? transverse momentum. The prompt ? c cross-sections are combined with existing measurements of prompt J/? production to derive the fraction of prompt J/? produced in feed-down from ? c decays. The fractions of ? c1 and ? c2 produced in b-hadron decays are also measured.