Measurement of the production cross-section of $\psi(2S) \to J/\psi ( \to \mu^{+} \mu^{-}) \pi^{+} \pi^{-}$ in pp collisions at $ \sqrt{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.