Universal suppression of heavy quarkonium production in pA collisions at low transverse momentum

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 N-c limit between the two formalisms to describe the heavy quarkonium production: the nonrelativistic QCD and the color-evaporation model. This provides an important probe to the saturation momentum at small x in the big nucleus. We also comment on the phenomenological applications of our results.