Towards an automated tool to evaluate the impact of the nuclear modification of the gluon density on quarkonium, D and B meson production in proton–nucleus collisions

Abstract

We propose a simple and model-independent procedure to account for the impact of the nuclear modification of the gluon density as encoded in nuclear collinear PDF sets on two-to-two partonic hard processes in proton–nucleus collisions. This applies to a good approximation to quarkonium, D and B meson production, generically referred to $$\mathcal {H}$$ . Our procedure consists in parametrising the square of the parton scattering amplitude, $${\mathcal {A}}_{gg \rightarrow {\mathcal {H}} X}$$ and constraining it from the proton–proton data. Doing so, we have been able to compute the corresponding nuclear modification factors for $$J/\psi $$ , $$\Upsilon $$ and $$D^0$$ as a function of y and $$P_T$$ at $$\sqrt{s_\mathrm{NN}}=5$$ and 8 TeV in the kinematics of the various LHC experiments in a model independent way. It is of course justified since the most important ingredient in such evaluations is the probability of each kinematical configuration. Our computations for D mesons can also be extended to B meson production. To further illustrate the potentiality of the tool, we provide – for the first time – predictions for the nuclear modification factor for $$\eta _c$$ production in $$p$$ Pb collisions at the LHC.