Inclusive J/$ψ$ production at mid-rapidity in pp collisions at $\sqrt{s}$ = 5.02 TeV


Inclusive J/$\psi$ production is studied in minimum-bias proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 5.02 TeV by ALICE at the CERN LHC. The measurement is performed at mid-rapidity ($|y| <~ 0.9$) in the dielectron decay channel down to zero transverse momentum $p_{\rm T}$, using a data sample corresponding to an integrated luminosity of $L_{\rm int} = 19.4 \pm$ 0.4 nb$^{-1}$. The measured $p_{\rm T}$-integrated inclusive J/$\psi$ production cross section is d$\sigma$/d$y$ = 5.64 $\pm$ 0.22 (stat.) $\pm 0.33$ (syst.) $\pm 0.12$ (lumi.) $\mu$b. The $p_{\rm T}$-differential cross section d$^{2} \sigma$/d$p_{\rm T}$d$y$ is measured in the $p_{\rm T}$ range 0$-$10 GeV/$c$ and compared with state-of-the-art QCD calculations. The J/$\psi$ $\langle p_{\rm T} \rangle$ and $\langle p_{\rm T}^{2} \rangle$ are extracted and compared with results obtained at other collision energies.


JHEP 10 (2019) 084
HEP Data
e-Print: arXiv:1905.07211 | PDF | inSPIRE

Figure 1

Same-event opposite-sign dielectron invariant mass distributions for several $\pt$-intervals with signal (blue), correlated background (green), and combinatorial background (red) components.

Figure 2

Left: Inclusive $\jpsi$ cross section as a function of rapidity compared to the ALICE results at forward rapidity~ and to calculations from~ to which a non-prompt component is added as computed in~. Right: Inclusive $\jpsi$ cross section at mid-rapidity~ as a function of collision energy compared to the calculations from ~. The data points from PHENIX and STAR, both at $\s=0.2$~TeV, are slightly shifted for improved visibility.

Figure 3

$\pT$-differential inclusive $\jpsi$ cross section compared with prompt $\jpsi$ calculations from NLO NRQCD~ and LO NRQCD+CGC~ and non-prompt $\jpsi$ calculations from FONLL~. The calculations for the prompt and non-prompt components are shown separately in the left panel while in the right panel the FONLL calculation is added to the prompt $\jpsi$ calculations.

Figure 4

$\pT$-differential inclusive $\jpsi$ cross section compared with ATLAS~ and CMS~ results at mid-rapidity. Luminosity uncertainties are indicated in the legend, except in the case of ATLAS for which these are included in the boxes.

Figure 5

The $\MeanPt$ (lower panel) and $\MeanPtSq$ (upper panel) of inclusive $\jpsi$ at mid-rapidity as a function of the collision energy. These results are compared to previous results from ALICE at LHC~, Tevatron~, RHIC~ and SPS~.