Abstract

The ALICE Collaboration at the LHC has measured the J/psi and psi' photoproduction at mid-rapidity in ultra-peripheral Pb-Pb collisions at root s(NN) = 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 mu b(-1). The cross section for coherent and incoherent J/psi production in the rapidity interval -0.9 < y < 0.9, are d sigma(coh)(J/psi)/dy = 2.38(-0.24)(+0.34)(sta + sys) mb and d sigma(inc)(J/psi)/dy = 0.98(-0.17)(+0.19)(sta + sys) mb and , respectively. The results are compared to theoretical models for J/psi production and the coherent cross section is found to be in good agreement with those models incorporating moderate nuclear gluon shadowing at Bjorken-x around 10(-3), such as EPS09 parametrization. In addition the cross section for the process gamma gamma -> e(+)e(-) has been measured and found to be in agreement with models implementing QED at leading order.

Autore Pugliese

• Di Bari Domenico , Fiore Enrichetta Maria , Volpe Giacomo

Tutti gli autori

• DI BARI D.;FIORE E.M.;VOLPE G.

Titolo volume/Rivista

Non Disponibile

Anno di pubblicazione

2013

ISSN

1434-6044

ISBN

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Numero di citazioni Wos

88

Ultimo Aggiornamento Citazioni

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Numero di citazioni Scopus

96

Ultimo Aggiornamento Citazioni

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Settori ERC

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Codici ASJC

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