  The nuclear suppression of heavy quarkonium production at low transverse
momentum in pA collisions in high energy scatterings is investigated in the
small-x factorization formalism. A universal suppression is found in the large
Nc limit between the two formalisms to describe the heavy quarkonium
production: the non-relativistic QCD (NRQCD) and the color-evaporation model
(CEM). This provides an important probe to the saturation momentum at small-x
in big nucleus. We also comment on the phenomenological applications of our
results.
