Impact of dijet and D-meson data from 5.02 TeV p+Pb collisions on nuclear PDFs

We discuss the new constraints on gluon parton distribution function (PDF) in lead nucleus, derivable with Hessian PDF reweighting method from 5.02 TeV p+Pb measurements of dijet (CMS) and D0-meson (LHCb) nuclear modification ratios. The impact is found to be significant, placing stringent mid- previously unconstrained small-x regions. CMS data confirm existence anti-shadowing onset shadowing, as well reduce uncertainties larger-x region. LHCb D0 data, reaching down x ∼ 10−5 derived a NLO perturbative QCD approach, provide remarkable reduction strong direct evidence shadowing. Furthermore, we find good description even zero transverse momentum within purely DGLAP-based approach without need for imposing any non-linear effects. Importantly, obtained are mutually fully consistent, supporting universality PDFs hard-scattering processes.