A QCD analysis of LHCb D-meson data in p+Pb collisions
Abstract
We scrutinize the recent LHCb data for D0-meson production in p+Pb collisions within a next-to-leading order QCD framework. Our calculations are performed in the SACOT-mT 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.
Main Authors
Format
Articles
Research article
Published
2020
Series
Subjects
Publication in research information system
Publisher
Springer; Societa Italiana di Fisica
The permanent address of the publication
https://urn.fi/URN:NBN:fi:jyu-202005193320Use this for linking
Review status
Peer reviewed
ISSN
1126-6708
DOI
https://doi.org/10.1007/JHEP05(2020)037
Language
English
Published in
Journal of High Energy Physics
Citation
- Eskola, K. J., Helenius, I., Paakkinen, P., & Paukkunen, H. (2020). A QCD analysis of LHCb D-meson data in p+Pb collisions. Journal of High Energy Physics, 2020(5), Article 37. https://doi.org/10.1007/JHEP05(2020)037
Funder(s)
Research Council of Finland
Research Council of Finland
Funding program(s)
Academy Research Fellow, AoF
Academy Project, AoF
Akatemiatutkija, SA
Akatemiahanke, SA

Additional information about funding
We wish to thank Michael Winn and Yanxi Zhang for discussions and help concerning the LHCb data. The Academy of Finland projects 297058 (K.J.E.) and 308301 (H.P. and I.H.), and the Magnus Ehrnrooth Foundation (P.P.) are acknowledged for financial support. Further support was provided by Ministerio de Ciencia e Innovaci´on of Spain under project FPA2017-83814-P; Unidad de Excelencia Mar´ıde Maetzu under project MDM-2016-0692; ERC-2018-ADG-835105 YoctoLHC; and Xunta de Galicia (Conseller´ıa de Educaci´on) and FEDER (P.P.). The Finnish IT Center for Science (CSC) is acknowledged for the computing time within the project jyy2580.
Copyright© The Authors. Article funded by SCOAP3.