Inclusive J/ψ production in pp collisions at √s=2.76 TeV

The ALICE Collaboration has measured inclusive J/ψ production in pp collisions at a center-of-mass energy √ s = 2.76 TeV at the LHC. The results presented in this Letter refer to the rapidity ranges |y| <0.9 and 2.5 <y <4 and have been obtained by measuring the electron and muon pair decay channels, respectively. The integrated luminosities for the two channels are Le int = 1.1 nb−1 and Lμ int = 19.9 nb−1, and the corresponding signal statistics are Ne+e− J/ψ = 59 ± 14 and Nμ + μ − J/ψ = 1364 ± 53. We present dσJ/ψ /dy for the two rapidity regions under study and, for the forward-y range, d2σJ/ψ /dy dpt in the transverse momentum domain 0 <pt <8 GeV/c. The results √ are compared with previously published results at s = 7 TeV and with theoretical calculations