This page provides numerical table files for the
computation of CT18
nexttoleading order (NLO) and
nexttonexttoleading order (NNLO) parton distribution
functions. They can be interpolated with the help
of a
standalone Fortran interface
and
demonstration program
, as well as the tables with interpolated values of the
QCD coupling alpha_s and PDFs.
A simple C++ interface for the CTEQTEA PDFs with
CTEQ6.6 or later can be found
here. ATTENTION: The format of the PDF table files (with the extension .pds) and the Fortran interface were revised in 2012 to provide interpolation of the energy dependence of the QCD running coupling alpha_s using a table of alpha_s values stored inside the .pds file. The pre2012 PDF table files are partly incompatible with the new format. They can be interpolated by the 2012 interface, but without computing alpha_s. 
PDF set  Description and links to the table files  Authors or main contact  References  Date  Additional resources 
CT18 NNLO 
*Generalpurpose
NNLO central set + 58 eigenvector sets
(LHAPDF)
*PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.1160.120 and 0.1100.124 . The recommended 90% C.L. uncertainty estimate is 0.116  0.120. 
T.J. Hou et. al.

arXiv:1912.10053  12/2019 
Plots of L2 sensitivities 
CT18 NLO 
*Generalpurpose
NLO central set + 58 eigenvector sets
(LHAPDF)
*PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.1160.120 and 0.1100.124 . The recommended 90% C.L. uncertainty estimate is 0.116  0.120. 
T.J. Hou et. al. 
arXiv:1912.10053 
12/2019 

CT18Z NNLO 
*Generalpurpose
NNLO central set + 58 eigenvector sets
(LHAPDF)
*PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.1160.120 and 0.1100.124 . The recommended 90% C.L. uncertainty estimate is 0.116  0.120. 
T.J. Hou et. al.

arXiv:1912.10053 
12/2019 
Plots of L2 sensitivities 
CT18Z NLO 
*Generalpurpose
NLO central set + 58 eigenvector sets
(LHAPDF)
*PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.1160.120 and 0.1100.124 . The recommended 90% C.L. uncertainty estimate is 0.116  0.120. 
T.J. Hou et. al. 
arXiv:1912.10053 
12/2019 

CT18A NNLO 
*Generalpurpose
NNLO central set + 58 eigenvector sets
(LHAPDF)
*PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.1160.120 and 0.1100.124 . The recommended 90% C.L. uncertainty estimate is 0.116  0.120. 
T.J. Hou et. al.

arXiv:1912.10053 
12/2019 

CT18A NLO 
*Generalpurpose
NLO central set + 58 eigenvector sets
(LHAPDF)
*PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.1160.120 and 0.1100.124 . The recommended 90% C.L. uncertainty estimate is 0.116  0.120. 
T.J. Hou et. al. 
arXiv:1912.10053 
12/2019 

CT18X NNLO 
*Generalpurpose
NNLO central set + 58 eigenvector sets
(LHAPDF)
*PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.1160.120 and 0.1100.124 . The recommended 90% C.L. uncertainty estimate is 0.116  0.120. 
T.J. Hou et. al.

arXiv:1912.10053 
12/2019 

CT18X NLO 
*Generalpurpose
NLO central set + 58 eigenvector sets
(LHAPDF)
*PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.1160.120 and 0.1100.124 . The recommended 90% C.L. uncertainty estimate is 0.116  0.120. 
T.J. Hou et. al. 
arXiv:1912.10053 
12/2019 