Inclusive quarkonium production in pp collisions at $\sqrt{s} = 5.02$ TeV

This article reports on the inclusive production cross section of several quarkonium states, $\mathrm{J}/\psi$, $\psi {\rm (2S)}$, $\Upsilon\rm(1S)$, $\Upsilon\rm(2S)$, and $\Upsilon\rm(3S)$, measured with the ALICE detector at the LHC, in \pp collisions at $\sqrt{s} = 5.02$ TeV. The analysis is performed in the dimuon decay channel at forward rapidity ($2.5 <~ y <~ 4$). The measured cross sections, assuming unpolarized quarkonia, are: $\sigma_{\mathrm{J}/\psi} = 5.88 \pm 0.03 \pm 0.34\ \mu$b, $\sigma_{\psi {\rm (2S)}} = 0.87 \pm 0.06 \pm 0.10\ \mu$b, $\sigma_{\Upsilon\rm(1S)} = 45.5 \pm 3.9 \pm 3.5$ nb, $\sigma_{\Upsilon\rm(2S)} = 22.4 \pm 3.2 \pm 2.7$ nb, and $\sigma_{\Upsilon\rm(3S)} = 4.9 \pm 2.2 \pm 1.0$ nb, where the first (second) uncertainty is the statistical (systematic) one. The transverse-momentum ($p_{\rm T}$) and rapidity ($y$) differential cross sections for $\mathrm{J}/\psi$, $\psi {\rm (2S)}$, $\Upsilon\rm(1S)$, and the $\psi {\rm (2S)}$-to-$\mathrm{J}/\psi$ cross section ratios are presented. For the first time, the cross sections of the three $\Upsilon$ states, as well as the $\psi {\rm (2S)}$ one as a function of $p_{\rm T}$ and $y$, are measured at $\sqrt{s} = 5.02$ TeV at forward rapidity. These measurements also significantly extend the $\mathrm{J}/\psi$ $p_{\rm T}$ reach with respect to previously published results. A comparison with ALICE measurements in pp collisions at $\sqrt{s} = 2.76$, 7, 8, and 13 TeV is presented and the energy dependence of quarkonium production cross sections is discussed. Finally, the results are compared with the predictions from several production models.

 

Submitted to: EPJC
e-Print: arXiv:2109.15240 | PDF | inSPIRE
CERN-EP-2021-197

Figure 2

Transverse momentum dependence of the inclusive \jpsi cross section. The measurements are compared to theoretical calculations from Refs.~ (left) and Refs.~ (right). The calculations of the non-prompt contribution~ are also shown separately. See text for details.

Figure 3

Rapidity dependence of the inclusive \jpsi cross section. The measurements are compared to theoretical calculations from Refs.~.

Figure 5

The left and right panels show the \pt dependence for the inclusive \psitwos production cross section in \pp collisions at $\s = 5.02$~TeV. The results are compared with the theory predictions based on NRQCD~ (left) and CEM~ (right) models. The calculation of the non-prompt contribution from FONLL calculations~ are also shown separately. See text for details

Figure 6

Rapidity dependence for the inclusive \psitwos production cross section in \pp collisions at $\s = 5.02$~TeV. The results are compared with the theory predictions based on NRQCD+CGC~ and ICEM~ models. See text for details

Figure 8

Transverse momentum dependence of the \upsones cross section (left) and \rapidity dependence of the \upsones, \upstwos, and \upsthrees (right) measured by ALICE and CMS. The two panels also show theoretical calculations~. See text for details.

Figure 9

Transverse momentum dependence of the inclusive \jpsi cross section, at forward \rapidity, measured in pp collisions at $\sqrt{s} = 5.02$, 7~, 8~, and 13~ TeV (top panel), and ratio of the measurements at 5.02, 7, and 8 TeV to the 13 TeV data (bottom panel). The data are compared with the NRQCD theoretical calculations from Butenschön~\etal~+ FONLL (left panel)~ and with theoretical calculations from ICEM + FONLL (right panel)~.

Figure 11

Transverse momentum dependence of the inclusive \psitwos cross section, at forward \rapidity, measured in pp collisions at $\s = 5.02$, 7~, 8~, and 13~ TeV (top panel), and ratio of the measurements at 5.02, 7, 8 TeV to the 13 TeV data (bottom panel). The data are compared with the NRQCD theoretical calculations from Butenschön~\etal~+ FONLL (left panel)~ and with theoretical calculations from ICEM + FONLL (right panel)~.

Figure 14

Inclusive \psitwos-to-\jpsi cross section ratio (left) and \jpsi, \psitwos, \upsones, \upstwos, and \upsthrees \pt-integrated cross section per unit of rapidity (right) as a function of the collision energy in pp collisions~. In the left panel, the systematic boxes include the BR uncertainties from both resonances, on top of the MC input and signal extraction systematic uncertainties. The 13 TeV data point is computed from the published individual \jpsi and \psitwos \pt-integrated cross sections. The statistical and systematic uncertainties are assumed to be uncorrelated between the resonances when computing the ratio. In the right panel, the luminosity and branching ratio uncertainties are included in the systematic boxes. The data are compared with theoretical calculations from ICEM + FONLL~.