Rapidity dependence of the inclusive J/ψ production in p bar p collisions at √s = 1.8 TeV

We have studied the J/ψ production in p anti p collisions at √s = 1.8 TeV with the D null detector at the Fermilab Tevatron, using a μ+μ- data sample collected during the 1994-95 running period. We have measured the inclusive J/ψ production cross section as a function of the J/ψ transverse momentum, PTJ/ψ in the central and forward rapidity regions. The new measurement of the cross section dσ/dpTJ/ψ for |ηJ/ψ| < 0.6 is in a good agreement with the CDF and earlier D null results. The cross section measurement dσ/dpTJ/ψ for 2.5 < |ηJ/ψ| < 3.7 covers the pTJ/ψ range from 1 to 16 GeV/c. We combine the measurements in several |ηJ/ψ| regions to discuss dσ/dηJ/ψ for pTJ/ψ > 8 GeV/c. The data are compared with the next-to- leading order (NLO) QCD calculations, which take into account different J/ψ production mechanisms