# CT10 NLO and NNLO parton distribution functions

 This page provides numerical table files for the computation of CT10 next-to-leading order (NLO) and next-to-next-to-leading 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. (A simple C++ interface for the CTEQ-TEA 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 pre-2012 PDF table files are partly incompatible with the new format. They can be interpolated by the 2012 interface, but without computing alpha_s. All CT10 NLO and NNLO table files have been converted into the new format. If you are looking for the 2010 version of the interface and table files, click here.  Naming conventions for the NLO and NNLO sets. In comparisons of the NLO and NNLO calculations, the CT10 NNLO set can be used as a counterpart for either the CT10 NLO set or the CT10W NLO set. The CT10 NNLO set includes a part of the data sample for D0 Run-2 W charge asymmetry that is included in the CT10W NLO fit, but is not included in the CT10 NLO fit. The W charge asymmetry data primarily modifies the slope of the ratio d(x,Q)/u(x,Q) at large momentum fractions x. Apart from the difference in the d/u ratio at x>0.1, the CT10 NLO and CT10W NLO PDFs provide very similar predictions.

## Available PDF sets

See the header of the Fortran interface for further explanations.

 PDF set Description and links to the table files Authors or main contact References Date Additional resources CT10H NNLO * Four extreme sets of CT10H PDFs; for studying gg -> H cross sections at the LHC; at NNLO S. Dulat et. al. arXiv:1310.7601 10/2013 CT10C NNLO * Four sets of CT10 intrinsic charm PDFs; at NNLO S. Dulat et. al. arXiv:1309.0025 08/2013 CT10 NNLO *General-purpose NNLO central set + 50 eigenvector sets *PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.116-0.120 and 0.110-0.130. The recommended 90 % C.L. uncertainty estimate is 0.116 - 0.120. P. Nadolsky et al. arXiv:1302.6246 05/2012 Additional figures CT10 NLO *General-purpose NLO central set + 52 eigenvector sets *PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.116-0.120 and 0.112-0.127. The recommended 90 % C.L. uncertainty estimate is 0.116 - 0.120. H.-L. Lai et al. arXiv:1007.2241 07/2010 Additional figures CT10W NLO *General-purpose NLO central set + 52 eigenvector sets *PDF sets with a varied strong coupling alpha_s(M_Z) in the ranges 0.116-0.120 and 0.112-0.127. The recommended 90 % C.L. uncertainty estimate is 0.116 - 0.120. H.-L. Lai et al. arXiv:1007.2241 07/2010 CT10F3 CT10F4 CT10WF3 CT10WF4 NLO CT10/CT10W PDF sets in 3-flavor and 4-flavor schemes, for two alternative choices of alpha_s(Q) in these schemes. These PDF sets are obtained by evolving the CT10(W) NLO parametrizations (obtained in the variable flavor scheme) from the initial scale Q0 to higher Q values using the 3-flavor or 4-flavor DGLAP evolution. See README in the .zip file for further explanations. H.-L. Lai et al. arXiv:1007.2241 Updated on 05/2012

Depository of CT10 PDFs, 2010 version
Previous families of PDFs: CTEQ6-CTEQ6.6

This website is partially supported by the U.S. National Science Foundation under Grant No. PHY-0855561.