SM PDF fits#

The figures below demonstrate the impact of the top quark data on our study on the gluon PDF. Three PDFs are compared:

  • NNPDF4.0-notop: all top quark data excluded;

  • Fit H: all top quark data in our study is included (see the dataset section for a detailed list);

  • NNPDF4.0: the NNPDF PDF set published alongside Ref. [Ball and others, 2022].



A comparison of the gluon PDF resulting from each fit is displayed below, normalised to the central value of NNPDF4.0-notop. On the right, the PDF uncertainties are compared.

We observe that the inclusion of top quark data has a marked impact on the gluon PDF, particularly in the region \(x \in [0.1,0.5]\). The central value of the PDF shifts downwards, and the PDF uncertainty is reduced.

This effect is already observed in the comparison between NNPDF4.0 and NNPDF4.0-notop, however it is clearly enhanced by the inclusion of the latest top quark data.

../_images/fitH_vs_notop_vs_40_g_172.png ../_images/fitH_vs_notop_vs_40_g_172_unc.png


The same comparison is made below at the level of the gluon-gluon luminosity.

../_images/fitH_gg_lumi.png ../_images/fitH_gg_lumi_unc.png