New parton distribution functions from a global analysis of quantum chromodynamics

TLDR

The authors introduce new CTEQ‑TEA PDFs at LO, NLO, and NNLO derived from a global QCD analysis. The PDFs are supplied as central and Hessian error sets, with flexible parametrizations and additional (N)NLO sets spanning various αs values and GM‑VFN schemes for heavy partons. Compared to earlier CT PDFs, the new sets incorporate LHC and D0 data, use more flexible parametrizations yielding improved quark‑flavor fits, and deliver updated predictions for key LHC processes such as 13 TeV Higgs production.

Abstract

We present new parton distribution functions (PDFs) up to next-to-next-to-leading order (NNLO) from the CTEQ-TEA global analysis of quantum chromodynamics. These differ from previous CT PDFs in several respects, including the use of data from LHC experiments and the new D0 charged lepton rapidity asymmetry data, as well as the use of more flexible parametrization of PDFs that, in particular, allows a better fit to different combinations of quark flavors. Predictions for important LHC processes, especially Higgs boson production at 13 TeV, are presented. These CT14 PDFs include a central set and error sets in the Hessian representation. For completeness, we also present the CT14 PDFs determined at the leading order (LO) and the next-to-leading order (NLO) in QCD. Besides these general-purpose PDF sets, we provide a series of (N)NLO sets with various $\alpha_s$ values and additional sets in general-mass variable flavor number (GM-VFN) schemes, to deal with heavy partons, with up to 3, 4, and 6 active flavors.