Measurement of prompt $\psi$(2S) production cross sections in proton-lead and proton-proton collisions at $\sqrt{s_{{}_{\mathrm{N}\mathrm{N}}}}=$ 5.02 TeV

Measurements of prompt $\psi$(2S) meson production cross sections in proton-lead (pPb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of $\sqrt{s_{{}_{\mathrm{N}\mathrm{N}}}}=$ 5.02 TeV are reported. The results are based on pPb and pp data collected by the CMS experiment at the LHC, corresponding to integrated luminosities of 34.6 nb${}^{-1}$ and 28.0 pb${}^{-1}$, respectively. The nuclear modification factor $R_{\mathrm{p}\mathrm{P}\mathrm{b}}$ is measured for prompt $\psi$(2S) in the transverse momentum range 4 $<$ p${}_{\mathrm{T}}$ $<$ 30 GeV$\mathrm{/}c$ and the center-of-mass rapidity range $-$2.4 $< y_$\mathrm{c}\mathrm{m}$ <$\mathrm{1.93.}Theresultson$\psi$(2S)$R_$\mathrm{p}\mathrm{P}\mathrm{b}$$ are compared to the corresponding modification factor for prompt J$\mathrm{/}\psi$ mesons. The results point to different nuclear effects at play in the production of the excited charmonium state compared to the ground state, in the region of backward rapidity and for p${}_{\mathrm{T}}$ $<$ 10 GeV$\mathrm{/}c$.