Abstract

The ALICE Collaboration at the LHC has measured the J/ψ and ψ photoproduction at mid-rapidity in ultra-peripheral Pb–Pb collisions at √ sNN = 2.76 TeV. The charmonium is identified via its leptonic decay 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 23 μb−1. The cross section for coherent and incoherent J/ψ production in the rapidity interval −0.9 < y < 0.9, are dσcoh J/ψ/dy = 2.38+0.34 −0.24(sta +sys) mb and dσinc J/ψ/dy = 0.98+0.19 −0.17(sta + sys) mb, respectively. The results are compared to theoretical models for J/ψ production and the coherent cross section is found to be in good agreement with those models incorporating moderate nuclear gluon shadowing at Bjorkenx around 10−3, such as EPS09 parametrization. In addition the cross section for the process γγ →e + e − has been measured and found to be in agreement with models implementing QED at leading order.

Autore Pugliese

• Bruno Giuseppe Eugenio

Tutti gli autori

• Bruno G.E. , et al.

Titolo volume/Rivista

EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS

Anno di pubblicazione

2013

ISSN

1434-6052

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

Non Disponibile

Numero di citazioni Scopus

2

Ultimo Aggiornamento Citazioni

2017-04-22 03:20:59

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile