  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.

High Energy Physics - Phenomenology;High Energy Physics - Experiment;Nuclear Experiment;Nuclear Theory