摘要
This article reports on the inclusive production cross section of several quarkonium states, J/psi, psi(2S), Upsilon(1S), Upsilon(2S), and Upsilon(3S), measured with the ALICE detector at the LHC, in pp collisions at root s = 5.02 TeV. The analysis is performed in the dimuon decay channel at forward rapidity (2.5 < y < 4). The integrated cross sections and transverse-momentum (p(T)) and rapidity (y) differential cross sections for J/psi, psi(2S), Upsilon(1S), and the psi(2S)-to-J/psi cross section ratios are presented. The integrated cross sections, assuming unpolarized quarkonia, are: sigma(J/psi) (p(T) < 20 GeV/c) = 5.88 +/- 0.03 +/- 0.34 mu b, sigma(psi(2S)) (p(T) < 12 GeV/c) = 0.87 +/- 0.06 +/- 0.10 mu b, sigma(Upsilon(1S)) (p(T) < 15 GeV/c) = 45.5 +/- 3.9 +/- 3.5 nb, sigma(Upsilon(2S)) (p(T) < 15 GeV/c) = 22.4 +/- 3.2 +/- 2.7 nb, and sigma(Upsilon(3S)) (p(T) < 15 GeV/c) = 4.9 +/- 2.2 +/- 1.0 nb, where the first (second) uncertainty is the statistical (systematic) one. For the first time, the cross sections of the three Upsilon states, as well as the psi(2S) one as a function of p(T) and y, are measured at root s = 5.02 TeV at forward rapidity. These measurements also significantly extend the J/psi p(T) reach and supersede previously published results. A comparison with ALICE measurements in pp collisions at root 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.