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On the theoretical and experimental uncertainties in the extraction of the J/ψ absorption cross section in cold nuclear matter

A. Rakotozafindrabe † , E. G. Ferreiro ‡ , F. Fleuret § and J. P. Lansberg ¶
† IRFU/SPhN, CEA Saclay,
91191 Gif-sur-Yvette Cedex, France
‡ Departamento de Fsica de Partculas, Universidad de Santiago de Compostela,
15782 Santiago de Compostela, Spain
§ Laboratoire Leprince Ringuet, École polytechnique, CNRS-IN2P3,
91128 Palaiseau, France
¶ Centre de Physique Théorique, École Polytechnique, CNRS,
91128 Palaiseau, France
E-mail: andry.rakotozafindrabe@cea.fr

Abstract. We investigate the cold nuclear matter effects on J/ψ production, whose understanding is fundamental to study the quark-gluon plasma. Two of these effects are of particular relevance: the shadowing of the parton distributions and the nuclear absorption of the c¯ c pair. If J/ψ's are not produced via a 2 → 1 process as suggested by recent theoretical works, one has to modify accordingly the way to compute the nuclear shadowing. This naturally induces differences in the absorption cross-section fit to the data. A careful analysis of these differences however requires taking into account the experimental uncertainties and their correlations, as done in this work for dAu collisions at √ s N N = 200 GeV, using several shadowing parametrisations.

PACS numbers: 25.75.Dw, 25.75.-q, 24.85.+p, 21.60.Ka Keywords: J/ψ production, heavy-ion collisions, cold nuclear matter effects 1. Introduction