Rapidity and transverse momentum dependence of inclusive J/Ψ production in pp collisions at s=7 TeV

Abstract

The ALICE experiment at the LHC has studied inclusive J/ψ production at central and forward rapidities in pp collisions at √s = 7 TeV. In this Letter, we report on the first results obtained detecting the J/ψ through the dilepton decay into e⁺e⁻ and μ⁺μ⁻ pairs in the rapidity ranges |y| < 0.9 and 2.5 < y < 4, respectively, and with acceptance down to zero pₜ. In the dielectron channel the analysis was carried out on a data sample corresponding to an integrated luminosity Lint = 5.6 nb⁻¹ and the number of signal events is N_{J/ψ} = 352 ± 32 (stat.) ± 28 (syst.); the corresponding figures in the dimuon channel are Lint = 15.6 nb⁻¹ and N_{J/ψ} = 1924 ± 77 (stat.) ± 144 (syst.). The measured production cross sections are σ_{J/ψ}(|y| < 0.9) = 10.7 ± 1.0 (stat.) ± 1.6 (syst.) +1.6 −2.3 (syst.pol.) μb and σ_{J/ψ}(2.5 < y < 4) = 6.31 ± 0.25 (stat.) ± 0.76 (syst.) +0.95 −1.96 (syst.pol.) μb. The differential cross sections, in transverse momentum and rapidity, of the J/ψ were also measured.