Inclusive J/$ψ$ production at midrapidity in pp collisions at $\sqrt{s}~=~13$ TeV

We report on the inclusive J/$\psi$ production cross section measured at the CERN Large Hadron Collider in proton-proton collisions at a centre-of-mass energy $\sqrt{s}~=~13$ TeV. The J/$\psi$ mesons are reconstructed in the $\rm e^{+} e^{-}$ decay channel and the measurements are performed at midrapidity ($|y|<~0.9$) in the transverse-momentum interval $0<~ p_{\rm T} <~40$ GeV/$c$, using a minimum bias data sample corresponding to an integrated luminosity $L_{\text{int}} = 32.2~\text{nb}^{-1}$ and an Electromagnetic Calorimeter triggered data sample with $L_{\text{int}} = 8.3~\mathrm{pb}^{-1}$. The $p_{\rm T}$-integrated J/$\psi$ production cross section at midrapidity, computed using the minimum bias data sample, is $\text{d}\sigma/\text{d}y|_{y=0} = 8.97\pm0.24~(\text{stat})\pm0.48~(\text{syst})\pm0.15~(\text{lumi})~\mu\text{b}$. An approximate logarithmic dependence with the collision energy is suggested by these results and available world data, in agreement with model predictions. The integrated and $p_{\rm T}$-differential measurements are compared with measurements in pp collisions at lower energies and with several recent phenomenological calculations based on the non-relativistic QCD and Color Evaporation models.

 

Submitted to: EPJC
e-Print: arXiv:2108.01906 | PDF | inSPIRE
Figure group

Figure 1

Invariant-mass distributions for SE \ee pairs in two \ptee intervals from the MB event analysis (left panels) and two \ptee intervals from the EMCal-triggered event analysis (right panels). The signal and background components obtained from the fit procedure are shown separately. For the top-right panel, the distributions are scaled for convenience by a factor of 2.

Figure 3

Inclusive \jpsi production cross section compared with calculations for the prompt \jpsi production cross section using ICEM~, NLO NRQCD~, LO NRQCD+CGC~ and for the non-prompt \jpsi from beauty-hadron feed-down using FONLL~ (left panel). Inclusive \jpsi production cross section compared with the corresponding calculations obtained as the sum of the prompt \jpsi component shown in the left panel and the non-prompt contribution from FONLL (right panel). The bottom panel shows the ratios between the model calculations and a fit to the data points. The bands illustrate the theoretical uncertainties centered around the ratio between the model calculation and the power-law fit to the data (see text for details).

Figure 4

Inclusive \pt-integrated \jpsi production cross section as a function of collision energy (left panel) and rapidity (right panel) compared with the ICEM~ and NRQCD+CGC~ model calculations. The midrapidity \pt-integrated production cross section values are measured by the PHENIX~, STAR~, CDF~ and ALICE~ collaborations. The forward-rapidity production cross section shown in the right panel is reported by ALICE in Ref.~