Rapidity and transverse momentum dependence of inclusive J/psi production in pp collisions at sqrt(s) = 7 TeV

The ALICE experiment at the LHC has studied inclusive J/ψJ/ψ production at central and forward rapidities in pp collisions at View the MathML sources=7 TeV. In this Letter, we report on the first results obtained detecting the J/ψJ/ψ through the dilepton decay into e+e−e+e− and μ+μ−μ+μ− pairs in the rapidity ranges |y|<0.9|y|<0.9 and 2.5<y<42.5<y<4, respectively, and with acceptance down to zero pTpT. In the dielectron channel the analysis was carried out on a data sample corresponding to an integrated luminosity Lint=5.6 nb−1Lint=5.6 nb−1 and the number of signal events is View the MathML sourceNJ/ψ=352±32(stat.)±28(syst.); the corresponding figures in the dimuon channel are Lint=15.6 nb−1Lint=15.6 nb−1 and View the MathML sourceNJ/ψ=1924±77(stat.)±144(syst.). The measured production cross sections are View the MathML sourceσJ/ψ(|y|<0.9)=10.7±1.0(stat.)±1.6(syst.)−2.3+1.6(syst.pol.)μb and View the MathML sourceσJ/ψ(2.5<y<4)=6.31±0.25(stat.)±0.76(syst.)−1.96+0.95(syst.pol.)μb. The differential cross sections, in transverse momentum and rapidity, of the J/ψJ/ψ were also measured.