Suppression of inclusive J/$\mathbfψ$ and $\mathbfψ$(2S) production in p-Pb collisions with ALICE at the LHC

Abstract

The ALICE Collaboration has studied inclusive J/$ψ$ and $ψ$(2S) production in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV with the Muon Spectrometer. The measurement was performed at forward (2.03 $<$ $y_{\rm cms}$ $<$ 3.53) and backward ($-$4.46 $<$ $y_{\rm cms}$ $<$ $-$2.96) centre of mass rapidities. The nuclear modification factor of J/$ψ$ and $ψ$(2S) has been measured as a function of transverse momentum and event activity. Theoretical models based on nuclear shadowing, coherent energy loss or both are in reasonable agreement with the J/$ψ$ results but cannot describe the $ψ$(2S) behaviour. Other mechanisms must be invoked in order to explain the $ψ$(2S) suppression in p-Pb collisions.