Heavy quarkonium in the saturated environment of high-multiplicity pp collisions

High-multiplicity pp collisions exhibit features, traditionally associated with nuclear effects. Coherence
motivates to treat high-multiplicity pp, pA, and AA collisions on an equal footing. We rely on the
phenomenological parametrization for mean multiplicities of light hadrons and J=ψ, assuming their linear
dependence on Ncoll in pA collisions. The results of this approach underestimate the recently measured
production rate of J=ψ at very high hadronic multiplicities. The linear dependence of J=ψ multiplicity on
Ncoll is subject to predicted nonlinear corrections, related to mutual boosting of the saturation scales in
colliding dense parton clouds. A parameter-free calculation of the nonlinear corrections allows us to
explain data for pT-integrated yield of J=ψ at high hadronic multiplicities. Calculations are in a good
accord with data binned in several pT intervals as well. As was predicted, ϒ and J=ψ are equally suppressed
at forward rapidities in pA collisions. Consequently, their fractional multiplicities at forward rapidities in
pp collisions are equal as well, and their magnitude agrees with data.