ALICE CollaborationArmesto Pérez, NéstorGonzález Ferreiro, ElenaPajares Vales, CarlosSalgado López, Carlos Alberto2020-05-042020-05-042015Adam, J., Adamová, D., Aggarwal, M. M., Rinella, G. A., Agnello, M., Agrawal, N., ... & Ajaz, M. (2015). Coherent ψ (2S) photo-production in ultra-peripheral PbPb collisions at √sNN= 2.76 TeV. Physics Letters B, 751, 358-3700370-2693http://hdl.handle.net/10347/21980We have performed the first measurement of the coherent ψ(2S)photo-production cross section in ultra-peripheral Pb–Pb collisions at the LHC. This charmonium excited state is reconstructed via the ψ(2S) →l+l−and ψ(2S) →J/ψπ+π−decays, where the J/ψdecays into two leptons. The analysis is based on an event sample corresponding to an integrated luminosity of about 22μb−1. The cross section for coherent ψ(2S)production in the rapidity interval −0.9 <y <0.9is dσcohψ(2S)/dy =0.83 ±0.19 stat+syst mb. The ψ(2S)to J/ψcoherent cross section ratio is 0.34+0.08−0.07(stat+syst). The obtained results are compared to predictions from theoretical models.eng©2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.http://creativecommons.org/licenses/by/4.0/journal article10.1016/j.physletb.2015.10.0401873-2445open access