J/$\psi$ production and nuclear effects in p-Pb collisions at $\sqrt{s_{NN}}$=5.02 TeV

Inclusive J/$\psi$ production has been studied with the ALICE detector in p-Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV at the CERN LHC, in the rapidity domains 2.03 < y$_{cms}$ < 3.53 and −4.46 < y$_{cms}$ < −2.96, down to zero transverse momentum. The J/$\psi$ measurement is performed in the Muon Spectrometer through the $\mu^+\mu^−$ decay mode. In this Letter, the J/$\psi$ production cross section and the nuclear modification factor R$_{pPb}$ for the rapidities under study are presented. While at forward rapidity a suppression of the J/$\psi$ yield with respect to binary-scaled pp collisions is observed, in the backward region no suppression is present. The ratio of the forward and backward yields is also shown differentially in rapidity and transverse momentum. Theoretical predictions based on nuclear shadowing, as well as on models including, in addition, a contribution from partonic energy loss, are in fair agreement with the experimental results.