26-30 July 2021
Europe/Berlin timezone

NNPDF4.0: The Structure of the Proton at 1% Precision

26 Jul 2021, 17:00


Parallel session talk QCD and Hadronic Physics T06: QCD and Hadronic Physics


Roy Stegeman (University of Milan)


We present a new release of the NNPDF family of global analyses of the proton's parton distribution functions: NNPDF4.0. It includes a wealth of new experimental data from HERA and the LHC, from dijet cross-sections and isolated photons to single-top and top-quark pair differential distributions. The NNPDF4.0 methodology benefits from improved machine learning algorithms, in particular automated hyperparameter optimisation and stochastic gradient descent for neural network training, which has been validated extensively by means of closure tests and future tests. We demonstrate the stability of the results with respect to the choice of parameterisation basis. We compare NNPDF4.0 with its predecessor NNPDF3.1 as well as to other recent global fits, and study its phenomenological implications for representative collider observables. We assess the impact of representative datasets on specific PDF flavour combinations, such as the dijet and top quark data on the gluon, the Drell-Yan and neutrino DIS data on strangeness, and electroweak measurements on charm and quark flavour separation.

Collaboration / Activity Theoretical Particle Physics

Primary authors

Juan Rojo (VU Amsterdam and Nikhef) Roy Stegeman (University of Milan)

Presentation Materials