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  • Letter
  • Open Access

Intrinsic charm quark valence distribution of the proton

Richard D. Ball1, Alessandro Candido2,3, Juan Cruz-Martinez3, Stefano Forte2, Tommaso Giani4,5, Felix Hekhorn2,6,7, Giacomo Magni4,5, Emanuele R. Nocera8, Juan Rojo4,5 et al. (NNPDF Collaboration)

Juan Rojo4,5 and Roy Stegeman1 (NNPDF Collaboration)

  • 1The Higgs Centre for Theoretical Physics, University of Edinburgh, JCMB, KB, Mayfield Road, Edinburgh EH9 3JZ, Scotland
  • 2Tif Lab, Dipartimento di Fisica, Università di Milano and INFN, Sezione di Milano, Via Celoria 16, I-20133 Milano, Italy
  • 3CERN, Theoretical Physics Department, CH-1211 Geneva 23, Switzerland
  • 4Department of Physics and Astronomy, Vrije Universiteit, NL-1081 HV Amsterdam, The Netherlands
  • 5Nikhef Theory Group, Science Park 105, 1098 XG Amsterdam, The Netherlands
  • 6University of Jyväskylä, Department of Physics, P.O. Box 35, FI-40014 University of Jyväskylä, Finland
  • 7Helsinki Institute of Physics, P.O. Box 64, FI-00014 University of Helsinki, Helsinki, Finland
  • 8Dipartimento di Fisica, Università degli Studi di Torino and INFN, Sezione di Torino, Via Pietro Giuria 1, I-10125 Torino, Italy

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Phys. Rev. D 109, L091501 – Published 1 May, 2024

DOI: https://doi.org/10.1103/PhysRevD.109.L091501

Abstract

We provide a first quantitative indication that the wave function of the proton contains unequal distributions of charm quarks and antiquarks, i.e., a nonvanishing intrinsic valence charm distribution. A significant nonvanishing valence component cannot be perturbatively generated; hence, our results reinforce previous evidence that the proton contains an intrinsic (i.e., not radiatively generated) charm quark component. We establish our result through a determination of the parton distribution functions of charm quarks and antiquarks in the proton. We propose two novel experimental probes of this intrinsic charm valence component: D-meson asymmetries in Z+c-jet production at the LHCb experiment and flavor-tagged structure functions at the Electron-Ion Collider.

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Phys. Rev. D 109, L091501– Published 1 May, 2024
  • Received 26 October 2023
  • Accepted 14 March 2024
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