Intrinsic charm parton distribution functions from CTEQ-TEA global analysis.

We study the possibility of intrinsic (nonperturbative) charm in parton distribution functions (PDF) of the proton, within the context of the CT10 next-to-next-to-leading order global analysis. Three models for the intrinsic charm (IC) quark content are compared: (i) ĉ(x) = 0 (zero-IC model); (ii) ĉ(x) is parametrized by a valence-like parton distribution (BHPS model); (iii) ĉ(x) is parametrized by a sea-like parton distribution (SEA model). In these models, the intrinsic charm content, ĉ(x), is included in the charm PDF at the matching scale Qc = mc = 1.3 GeV. The best fits to data are constructed and compared. Correlations between the value of mc and the amount of IC are also considered. [ABSTRACT FROM AUTHOR]