J/psi production cross section and polarization with LHCb

Despite the large experimental and theoretical efforts, the J/psi production rate and states in hadronic collisions are not yet satisfactorily understood. The comparison between the J/psi differential cross section measurement and the most recent theoretical models shows a general good agreement but it is still unsatisfactory. The double differential J/psi 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/psi polarization with a full angular analysis, in both the polar and azimuthal angle.