The possibility of a (sizable) nonperturbative contribution to the charm
parton distribution function (PDF) in a nucleon is investigated together with
theoretical issues arising in its interpretation. Results from the global PDF
analysis are presented. The separation of the universal component of the
nonperturbative charm from the rest of the radiative contributions is discussed
and the potential impact of a nonperturbative charm PDF on LHC scattering
processes is illustrated. An estimate of nonperturbative charm magnitude in the
CT14 and CT14HERA2 global QCD analyses at the next-to-next-to leading order
(NNLO) in the QCD coupling strength is given by including the latest
experimental data from HERA and the Large Hadron Collider (LHC). A comparison
between different models of intrinsic charm is shown and prospects for standard
candle observables at the LHC are illustrated.Comment: 7 pages, 2 figures. Conference Proceedings of CIPANP2018, 13th
Conference on the Intersections of Particle and Nuclear Physics, May 29 -
June 3, 2018 Palm Springs, CA. Based on arXiv: 1707.00657, published in JHEP
1802 (2018) 05