Measurement of the production cross-section of ψ (2S) → J/ψ (→ μ + μ − ) π + π − in pp collisions at s = 7 TeV at ATLAS

The prompt and non-prompt production cross-sections for ψ (2S) mesons are measured using 2.1 fb −1 of pp collision data at a centre-of-mass energy of 7 TeV recorded by the ATLAS experiment at the LHC. The measurement exploits the ψ (2S) → J/ψ (→ μ + μ − ) π + π − decay mode, and probes ψ (2S) mesons with transverse momenta in the range 10 ≤ p T < 100 GeV and rapidity | y | < 2 . 0. The results are compared to other measurements of ψ (2S) production at the LHC and to various theoretical models for prompt and non-prompt quarkonium production.