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

Abstract

Abstract We present results on transverse momentum (pt) and rapidity (y) differential production cross sections, mean transverse momentum and mean transverse momen- tum square of inclusive J/ψ and ψ(2S) at forward rapid- ity (2.5 < y < 4) as well as ψ(2S)-to-J/ψ cross section ratios. These quantities are measured in pp collisions at cen- ter of mass energies √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 com- prehensive comparison to inclusive charmonium cross sec- tions measured at √s = 2.76, 7 and 8 TeV is performed. A comparison to non-relativistic quantum chromodynam- ics and fixed-order next-to-leading logarithm calculations, which describe prompt and non-prompt charmonium pro- duction respectively, is also presented. A good description of the data is obtained over the full pt range, provided that both contributions are summed. In particular, it is found that for pt > 15 GeV/c the non-prompt contribution reaches up to 50% of the total charmonium yield.