MMHT 2014 PDFs: LHAPDF grids
Here we enclose the LHAPDF 5 and 6 grid files corresponding to the MMHT 2014 PDFs, published in
L. A. Harland-Lang, A. D. Martin, P. Motylinski, R. S. Thorne
"Parton distributions in the LHC era: MMHT 2014 PDFs"
arXiv:1412.3989
Please reference this paper if you use the PDFs for a publication.
We provide LO, NLO and NNLO grids for the central fit and 50 eigvectors sets (corresponding to 25 eigenvectors in the '+' and '-' directions), for a 68% confidence interval. These are defined using the Hessian approach and dynamical tolerance criteria described in arXiv:0901.0002. Grids for the central fit + eigenvectors are provided for αS=0.135 and 0.118 at LO and NNLO, respectively, at or close to the best fit values. At NLO these are provided for αS=0.118 and 0.120. Finally, central grids are provided for a short and large ranges of αS values. For the short range, at LO, αS=0.134-0.136, at NLO αS=0.117-0.121 and at NNLO αS=0.118-0.120, in increments of 0.001. For the large range, no grids are available at LO, while at NLO and NNLO αS=0.108-0.128, in increments of 0.001. For further information about the uncertainties on αS, and the corresponding χ2 profiles across the large range, see:
L. A. Harland-Lang, A. D. Martin, P. Motylinski, R. S. Thorne
"Uncertainties on alpha_s in the MMHT2014 global PDF anaylsis and implications for SM predictions"
arXiv:1506.05682
****Important - Using LHAPDF 5 Grids****
The LHAPDF 5 Grids must be run using the older MSTW interpolation code provided with LHAPDF 5, as no further updates of version 5 are forseen. The number of eigenvector sets is hard-coded in the interpolation code and must be increased to account for the larger number of eigenvectors in the MMHT14 PDFs, compared to MSTW08. To achieve this, simply change the parameter 'nhess' on line 33 of 'src/wrapmstw.f' to 'nhess=2*25' (in the most up-to-date versions of LHAPDF 5 this currently reads 'nhess=2*23'), and recompile LHAPDF. Note that increasing this parameter will not affect the result of using the MSTW08 PDFs.
Central + eigenvector sets
Central sets, variable αS
Central + eigenvector sets, different flavour schemes
Central sets, variable αS, different flavour schemes
Central sets, variable mc, different flavour schemes
Central sets, variable mb, different flavour schemes
