Differential distributions for top-pair production in NNLO QCD + NLO EW

Electronic files with LHC 13 TeV predictions for specific CMS bins (unpublished) for 3 pdf sets (LUXqed, LUXqed17 and NNPDF3.1). Results for all 7 scale combinations and all pdf members are made available. We use mtop=173.3 GeV; all other parameters are described in the README file inside the tarball. Contains the usual 1-dim distributions. For the first time pT,top, pT,tbar and pT,avt are computed (same for the rapidity distributions). fastNLO tables with the pure QCD results are available here.

Note: The distribution in |y(top)| – |y(tbar)| corresponds to the LHC charge asymmetry. One should keep in mind that the calculation has not been optimized for extracting that asymmetry, however, and the MC error – while small for the differential distribution – will be substantial for the asymmetry. In the dedicated AC calculation arXiv:1711.03945 (see below) a dedicated effort has been made to extract the asymmetry with small MC error.

Credits: for all plots and results above please cite arXiv:1705.04105. We would like to thank Andrew Papanastasiou for his assistance in the derivation of some of the results.

Electronic files with the NNLO QCD + EW predictions for the ttbar charge asymmetry at the LHC 8 TeV and Tevatron from the publication: Czakon, Heymes, Mitov, Pagani, Tsinikos, Zaro: arXiv:1711.03945. The tarball includes two README files explaining separately the LHC and Tevatron results.

Electronic files with Tevatron differential distributions. The predictions are accurate to NNLO QCD + NLO EW and utilize dynamic scales. Predictions with a static scale are also available for easier comparison with previous calculations. Publication: Czakon, Heymes, Mitov, Pagani, Tsinikos, Zaro: arXiv:1712.04842. A README file explaining the results is included.

Electronic files with the top-quark-pair differential distributions in NNLO QCD + NLO EW for LHC at 8 TeV and 13 TeV from the publication: Czakon, Heymes, Mitov, Pagani, Tsinikos, Zaro: arXiv:1705.04105.

Results available for download (single tarball including a README file with explanations):

for the following four distributions: mtt, ytt, yavt and pTavt. As a default pdf set we use LUXqed. Results based on the NNPDF3.0QED pdf set are provided as well.

computed in NNLO QCD + NLO EW for the following distributions/bins:

  • mtt: {300.0, 360.0, 430.0, 500.0, 580.0, 680.0, 800.0, 1000.0, 1200.0, 1500.0, 2500.0} GeV
  • |ytt|: {0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.4}
  • |yavt|: {0.0, 0.2, 0.4, 0.6, 0.8, 1., 1.2, 1.4, 1.6, 1.8, 2.0, 2.5}
  • pTavt, pT leading top, pT trailing top: {0.0, 40.0, 80.0, 120.0, 160.0, 200.0, 240.0, 280.0, 330.0, 380.0, 430.0, 500.0, 800.0} GeV

Plots are available upon request (note that the leading/trailing top pT distributions are new and have not been published before). The pT distributions are computed with scale mT(t1)/2 and mT(t2)/2 for t1 and t2, respectively. We have checked that, as for the case of averaged top, the results are very close to the ones derived with scale HT/4.


Additional materials:

  • Additional plots for LHC 13 TeV that are not included in the above publication (correspond to Fig. 1 in the paper; multiplicative approach with NNPDF3.0QED):




  • Complete set of plots but for LHC 8 TeV (download as tar.gz file). These are not included in the above publication.
  • Zoom-in of the threshold region of Fig. 4 in the paper. This demonstrates that, as expected, the additive and multiplicative approaches agree for small pT and Mtt.



  • Additional material for the discussion in sec.3.2 (see top of page 9 of the paper): Here we demonstrate that at large PTavt, the differential cross-section at NLO QCD is driven by configurations containing hard top, hard antitop (with the two being almost back-to-back) and a soft jet. This can be seen from the following two figures.


This figure shows that the cross-section is dominated by “symmetric” configurations where the top and antitop have similar PT‘s. This is true for a range of PT‘s (two such cuts are chosen here: 500 GeV and 1000 GeV).




This figure shows that the peak of the cross-section (when PT(top) is large) corresponds to jets with small PT.