The ALICE collaboration performed the first rapidity-differential measurement of coherent J/ψ photopro- duction in ultra-peripheral Pb–Pb collisions at a center-of-mass energy √sNN = 5.02 TeV. The J/ψ is detected via its dimuon decay in the forward rapidity region (−4.0 < y < −2.5) for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of about 750 μb−1. The cross section for coherent J/ψ production is presented in six rapidity bins. The results are compared with theoretical models for coherent J/ψ photoproduction. These comparisons indicate that gluon shadowing effects play a role in the photoproduction process. The ratio of ψ′ to J/ψ coherent photoproduction cross sections was measured and found to be consistent with that measured for photoproduction off protons.

Coherent J/ψ photoproduction at forward rapidity in ultra-peripheral Pb–Pb collisions at √sNN = 5.02 TeV

Camerini P.;Contin G.;Faggin M.;Fragiacomo E.;Lea R.;Luparello G.;Margagliotti G. V.;Piano S.;Rui R.;Zaccolo V.;
2019-01-01

Abstract

The ALICE collaboration performed the first rapidity-differential measurement of coherent J/ψ photopro- duction in ultra-peripheral Pb–Pb collisions at a center-of-mass energy √sNN = 5.02 TeV. The J/ψ is detected via its dimuon decay in the forward rapidity region (−4.0 < y < −2.5) for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of about 750 μb−1. The cross section for coherent J/ψ production is presented in six rapidity bins. The results are compared with theoretical models for coherent J/ψ photoproduction. These comparisons indicate that gluon shadowing effects play a role in the photoproduction process. The ratio of ψ′ to J/ψ coherent photoproduction cross sections was measured and found to be consistent with that measured for photoproduction off protons.
File in questo prodotto:
File Dimensione Formato  
PLB_798(2019)134926_1-14.pdf

accesso aperto

Tipologia: Documento in Versione Editoriale
Licenza: Creative commons
Dimensione 1.42 MB
Formato Adobe PDF
1.42 MB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2951178
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 56
  • ???jsp.display-item.citation.isi??? 57
social impact