Despite the large experimental and theoretical efforts, the J/ψ production rate and states in hadronic collisions are not yet satisfactorily understood. The comparison between the J/ψ differential cross section measurement and the most recent theoretical models shows a general good Agreement but it is still unsatisfactory. The double differential J/ψ cross section has been measured at LHCb with 5 pb−1 out of the 37 pb−1 data sample recorded during the 2010 data taking, disentangling the prompt component and the component coming from the b-hadrons decays. With the full data sample LHCb aims to give a measurement of the prompt
J/ψ polarization with a full angular analysis, in both the polar and azimuthal angle
