6533b85cfe1ef96bd12bd338
RESEARCH PRODUCT
A QCD analysis of LHCb D-meson data in p plus Pb collisions
Petja PaakkinenPetja PaakkinenPetja PaakkinenKari J. EskolaKari J. EskolaIlkka HeleniusIlkka HeleniusHannu PaukkunenHannu Paukkunensubject
Nuclear and High Energy PhysicsParticle physicsFOS: Physical sciencesPartonhiukkasfysiikka01 natural sciences114 Physical sciencesHigh Energy Physics - Phenomenology (hep-ph)Factorization0103 physical sciencesD mesonRapiditylcsh:Nuclear and particle physics. Atomic energy. Radioactivityheavy ion phenomenology010306 general physicsParton showerNuclear ExperimentParticle Physics - PhenomenologyPhysicsQuantum chromodynamicsLarge Hadron Collider010308 nuclear & particles physicshep-phHeavy Ion PhenomenologyGluonHigh Energy Physics - Phenomenologylcsh:QC770-798High Energy Physics::Experimentdescription
We scrutinize the recent LHCb data for D$^0$-meson production in p+Pb collisions within a next-to-leading order QCD framework. Our calculations are performed in the SACOT-$m_{\rm T}$ variant of the general-mass variable-flavour-number scheme (GM-VFNS), which has previously been shown to provide a realistic description of the LHC p+p data. Using the EPPS16 and nCTEQ15 nuclear parton distribution functions (PDFs) we show that a very good agreement is obtained also in the p+Pb case both for cross sections and nuclear modification ratios in the wide rapidity range covered by the LHCb data. Encouraged by the good correspondence, we quantify the impact of these data on the nuclear PDFs by the Hessian reweighting technique. We find compelling direct evidence of gluon shadowing at small momentum fractions $x$, with no signs of parton dynamics beyond the collinear factorization. We also compare our theoretical framework to a fixed-order calculation supplemented with a parton shower. While the two frameworks differ in the absolute cross sections, these differences largely cancel in the nuclear modification ratios. Thus, the constraints for nuclear PDFs appear solid.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2020-05-08 |