This page provides
numerical table files for the computation of CT14
leading order (LO), nexttoleading order (NLO) and
nexttonexttoleading order (NNLO) parton distribution
functions. They can be interpolated with the help
of a NEW standalone
Fortran interface and demonstration
program, as well as the tables with interpolated
values of the QCD coupling alpha_s and PDFs. Parametrizations of CT14 PDFs are also available from the LHAPDF library, version 6. For backward compatibility, we also provide CT14 grids in the LHAPDF5 format. Note that, in order to call all 57 CT14 error PDF sets with LHAPDF 5.9.X, you must recompile LHAPDF with an updated CT wrapper. A simple C++ interface for the CTEQTEA PDFs with CTEQ6.6 or later can be found here. The new CT18 parton distributions 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 
CT14 NNLO  *Generalpurpose
NNLO
central set + 56 eigenvector sets *PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.1160.120 and 0.1110.123. The recommended 90% C.L. uncertainty estimate is 0.116  0.120. 
S. Dulat et.
al. 
arXiv:1506.07443  06/2015 
Additional figures 
CT14 NNLO MonteCarlo  NNLO central set + 1000 MonteCarlo replicas for alpha_s(M_Z)=0.118

T.J. Hou et. al. 
arXiv:1607.06066  07/2016 
Additional figures, MCGEN program for replica generation 
CT14HERA2 NNLO 
NNLO central set + 56 eigenvector sets

T.J. Hou et. al.  arXiv:1609.07968  09/2016  Additional figure 
CT14NF3 CT14NF4 CT14NF6 NNLO 
CT14 NNLO PDF sets in 3flavor, 4flavor and 6flavor schemes, for alternative choices of alpha_s(Q) in these schemes. These PDF sets are obtained by evolving the CT14 NNLO parametrizations (obtained in the variable flavor scheme) from the initial scale Q_{0} to higher Q values using the 3flavor, 4flavor or 6flavor DGLAP evolution. See README in the .zip file for further explanations.  S. Dulat et. al.  arXiv:1506.07443  06/2015 

CT14IC NNLO 
* Four
sets of CT14 intrinsic charm PDFs; at NNLO 
S. Dulat et. al. 
TBA  06/2015 

CT14 NLO  *Generalpurpose
NLO
central set + 56 eigenvector sets *PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.1160.120 and 0.1110.123. The recommended 90% C.L. uncertainty estimate is 0.116  0.120. 
S. Dulat et. al.  TBA  06/2015 

CT14 NLO MonteCarlo  NLO central set + 1000 MonteCarlo replicas for alpha_s(M_Z)=0.118

T.J. Hou et. al. 
arXiv:1607.06066  07/2016 
Additional figures, MCGEN program for replica generation 
CT14HERA2 NLO 
NLO central set + 56 eigenvector sets

T.J. Hou et. al.  arXiv:1609.07968  09/2016  
CT14NF3 CT14NF4 CT14NF6 NLO 
CT14 NLO PDF sets in 3flavor, 4flavor and 6flavor schemes, for alternative choices of alpha_s(Q) in these schemes. These PDF sets are obtained by evolving the CT14 NLO parametrizations (obtained in the variable flavor scheme) from the initial scale Q_{0} to higher Q values using the 3flavor, 4flavor or 6flavor DGLAP evolution. See README in the .zip file for further explanations.  S. Dulat et. al.  TBA  06/2015 
Additional figures 
CT14 LO  *Generalpurpose
LO
central sets 
S. Dulat et. al.  TBA  06/2015 

CT14NF3 CT14NF4 CT14NF6 LO 
CT14 LO PDF sets in 3flavor, 4flavor and 6flavor schemes, for alternative choices of alpha_s(Q) in these schemes. These PDF sets are obtained by evolving the CT14 LO parametrizations (obtained in the variable flavor scheme) from the initial scale Q_{0} to higher Q values using the 3flavor, 4flavor or 6flavor DGLAP evolution. See README in the .zip file for further explanations.  S. Dulat et. al.  TBA  06/2015  
CT14qed  The
31 sets of CT14qed PDFs for proton and neutron,
respectively. They are obtained by evolving the
PDFs at LO in the QED interaction and at NLO in the QCD
interaction from the initial scale Q_{0 },
where they are based on the CT14 NLO PDFs. The photon PDF includes the inelastic component only, in which the hadron dissociates, and it is described by a twoparameter ansatz,
coming from radiation off the valence quarks. (The needed Fortran codes are
included in the zip file. See README in the .zip file
for further explanations.) We also provide the CT14qed PDF files in the format of LHAPDF version 6 and LHAPDF version 5. 
C. Schmidt et. al.  arXiv:1509.02905  12/2015  
CT14qed_inc  The
31 sets of CT14qed_inc PDFs for proton and neutron,
respectively. They are obtained by evolving the
PDFs at LO in the QED interaction and at NLO in the QCD
interaction from the initial scale Q_{0 },
where they are based on the CT14 NLO PDFs. The photon PDF in the proton is inclusive, including both inelastic and elastic contributions, and at the initial scale it is equal to the sum of the (inelastic) CT14qed and the elastic component derived from the Equivalent Photon Approximation. The photon PDF in the neutron is identical to CT14qed, since there is no elastic component for the neutron.
(The needed Fortran codes are
included in the zip file. See README in the .zip file
for further explanations.) We also provide the CT14qed_inc PDF files in the format of LHAPDF version 6 and LHAPDF version 5. 
C. Schmidt et. al.  arXiv:1509.02905  05/2016  