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

## TL;DR

This paper measures the production of J/ψ and ψ(2S) particles at forward rapidity in proton-proton collisions at different energies, comparing results to theoretical models and previous data to understand their production mechanisms.

## Contribution

It provides new measurements of charmonium production at forward rapidity at 5.02 and 13 TeV, and compares these with theoretical predictions and earlier results.

## Key findings

- Non-prompt charmonium contribution reaches up to 50% for pT > 15 GeV/c.
- Good agreement with theoretical models when both prompt and non-prompt contributions are summed.
- Data extends understanding of charmonium production dependence on energy and transverse momentum.

## Abstract

We present results on transverse momentum ($p_{\rm T}$) 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 $p_{\rm T}$ range, provided that both contributions are summed. In particular, it is found that for $p_{\rm T}>15$ GeV/$c$ the non-prompt contribution reaches up to 50% of the total charmonium yield.