Energy dependence of forward-rapidity J/$\psi$ and $\psi (2S)$ production in pp collisions at the LHC

Abstract

We present results on transverse momentum ($p_{\mathrm{T}}$) and rapidity ($y$) differential production cross sections, mean transverse momentum and mean transverse momentum square of inclusive J/$\psi$ and $\psi (2S)$ at forward rapidity ($2.5<y<4$) as well as $\psi (2S)$-to-J/$\psi$ cross section ratios. These quantities are measured in pp collisions at center of mass energies $\sqrt{s}=5.02$ and 13 TeV with the ALICE detector. Both charmonium states are reconstructed in the dimuon decay channel, using the muon spectrometer. A comprehensive comparison to inclusive charmonium cross sections measured at $\sqrt{s}=2.76$, 7 and 8 TeV is performed. A comparison to non-relativistic quantum chromodynamics and fixed-order next-to-leading logarithm calculations, which describe prompt and non-prompt charmonium production respectively, is also presented. A good description of the data is obtained over the full $p_{\mathrm{T}}$ range, provided that both contributions are summed. In particular, it is found that for $p_{\mathrm{T}}>15$ GeV/$c$ the non-prompt contribution reaches up to 50% of the total charmonium yield.

26 pages, 10 captioned figures, 1 table, authors from page 21, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/3364