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Cold Nuclear Matter effects in Upsilon production in dAu collisions at RHIC
Rakotozafindrabe A., Ferreiro E.G., Fleuret F., Lansberg J.P., Matagne N.
Physique/Physique des Hautes Energies - Expérience
Physique/Physique des Hautes Energies - Phénoménologie
Physique/Physique Nucléaire Expérimentale
Physique/Physique Nucléaire Théorique
Cold Nuclear Matter effects in Upsilon production in dAu collisions at RHIC
A. Rakotozafindrabe1, 2, E. G. Ferreiro, F. Fleuret1, J. P. Lansberg3, N. Matagne
1 :  LLR - Laboratoire Leprince-Ringuet
CNRS : UMR7638 – IN2P3 – Polytechnique - X
Route de Saclay - 91128 Palaiseau Cedex
2 :  IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers (ex DAPNIA)
3 :  IPNO - Institut de Physique Nucléaire d'Orsay
CNRS : UMR8608 – IN2P3 – Université Paris XI - Paris Sud
IPN - 15, rue Georges Clemenceau - 91406 ORSAY CEDEX
We report on our recent study of Cold Nuclear Matter effects on the Upsilon production at RHIC in dAu collisions. The first experimental results available on the nuclear modification factor R_dAu have rather large uncertainties. They nevertheless allow to bring qualitative information on the nature of the nuclear effects at play on top of the usual nuclear absorption, since the latter is expected to lie in a quite small range around a value close to ten times smaller as for charmonia. At backward rapidities, the behavior of R_dAu hints at the presence of a gluon EMC effect, analogous to the quark EMC effect -- but possibly stronger. Mid rapidity measurements with a better precision are highly desirable to pin down the gluon anti-shadowing, still under debate. At forward rapidities, the data leave some room for an additional fractional energy loss mechanism, recently revived in the literature.


6 pages, 4 figures, Proceedings for the Sixth International Conference on Quarks and Nuclear Physics QNP2012 (April 2012, Ecole Polytechnique, Palaiseau, Paris France)

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