Centrality dependence of $\mathbfψ$(2S) suppression in p-Pb collisions at $\mathbf{\sqrt{{\textit s}_{\rm NN}}}$ = 5.02 TeV

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5.02 TeV
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The ALICE experiment has studied the $\psi$(2S) production in p-Pb collisions at $sqrt(s_{NN})$=5.02 TeV, in the forward (2.03<$y_{cms}$<3.53) and backward
(-4.46<$y_{cms}$<-2.96) center of mass rapidity regions. The production of $\psi(2S)$, reconstructed in the $\mu^{+}\mu^{-}$ decay channel,  is studied as a function of the event activity, and compared to the J/$\psi$ one in terms of double ratio $[\sigma_{\psi(2S)}/\sigma_{J/\psi}]_{pA}/[\sigma_{\psi(2S)}/\sigma_{J/\psi}]_{pp}$ or nuclear modification factors.
The $\psi$(2S) yields show a  decrease as a function of event activity and a stronger unexpected suppression of the $\psi(2S)$ nuclear modification factor,
with respect to the J/$\psi$ one, is observed at backward rapidity. The different J/$\psi$ and $\psi$(2S) behaviour is not explained by theoretical models based on nuclear parton shadowing and on coherent energy loss mechanisms, suggesting final state effects playing a sizeable role on the $\psi$(2S) production.