NNPDFpol2.0: a global determination of polarised PDFs and their uncertainties at next-to-next-to-leading order

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Main Authors: Cruz-Martinez, Juan, Hasenack, Toon, Hekhorn, Felix, Magni, Giacomo, Nocera, Emanuele R., Rabemananjara, Tanjona R., Rojo, Juan, Sharma, Tanishq, van Seeventer, Gijs
Format: Preprint
Published: 2025
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author Cruz-Martinez, Juan
Hasenack, Toon
Hekhorn, Felix
Magni, Giacomo
Nocera, Emanuele R.
Rabemananjara, Tanjona R.
Rojo, Juan
Sharma, Tanishq
van Seeventer, Gijs
author_facet Cruz-Martinez, Juan
Hasenack, Toon
Hekhorn, Felix
Magni, Giacomo
Nocera, Emanuele R.
Rabemananjara, Tanjona R.
Rojo, Juan
Sharma, Tanishq
van Seeventer, Gijs
contents We present NNPDFpol2.0, a new set of collinear helicity parton distribution functions (PDFs) of the proton based on legacy measurements of structure functions in inclusive neutral-current longitudinally polarised deep-inelastic scattering (DIS), and of W -boson, single-inclusive, and di-jet production asymmetries in longitudinally polarised proton-proton collisions. The determination is accurate to next-to-next-to-leading order in the strong coupling, and includes heavy quark mass corrections in the analysis of DIS data. Uncertainties due to missing higher-order corrections are systematically incorporated by means of a covariance matrix determined by scale variations. NNPDFpol2.0 is based on a machine learning methodology, that makes use of Monte Carlo sampling for the representation of uncertainties into PDFs, of a neural network for the parametrisation of PDFs, of stochastic gradient descent for the optimisation of PDF parameters, and of hyperoptimisation for the selection of the best fitting model. We study the impact on PDFs of higher-order corrections, of the positivity constraint, and of the data. We demonstrate two phenomenological applications of NNPDFpol2.0, specifically the determination of the proton spin fraction carried by gluons and quarks, and of theoretical predictions for single-hadron production in longitudinally polarised DIS and proton-proton collisions.
format Preprint
id arxiv_https___arxiv_org_abs_2503_11814
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle NNPDFpol2.0: a global determination of polarised PDFs and their uncertainties at next-to-next-to-leading order
Cruz-Martinez, Juan
Hasenack, Toon
Hekhorn, Felix
Magni, Giacomo
Nocera, Emanuele R.
Rabemananjara, Tanjona R.
Rojo, Juan
Sharma, Tanishq
van Seeventer, Gijs
High Energy Physics - Phenomenology
High Energy Physics - Experiment
Nuclear Experiment
Nuclear Theory
We present NNPDFpol2.0, a new set of collinear helicity parton distribution functions (PDFs) of the proton based on legacy measurements of structure functions in inclusive neutral-current longitudinally polarised deep-inelastic scattering (DIS), and of W -boson, single-inclusive, and di-jet production asymmetries in longitudinally polarised proton-proton collisions. The determination is accurate to next-to-next-to-leading order in the strong coupling, and includes heavy quark mass corrections in the analysis of DIS data. Uncertainties due to missing higher-order corrections are systematically incorporated by means of a covariance matrix determined by scale variations. NNPDFpol2.0 is based on a machine learning methodology, that makes use of Monte Carlo sampling for the representation of uncertainties into PDFs, of a neural network for the parametrisation of PDFs, of stochastic gradient descent for the optimisation of PDF parameters, and of hyperoptimisation for the selection of the best fitting model. We study the impact on PDFs of higher-order corrections, of the positivity constraint, and of the data. We demonstrate two phenomenological applications of NNPDFpol2.0, specifically the determination of the proton spin fraction carried by gluons and quarks, and of theoretical predictions for single-hadron production in longitudinally polarised DIS and proton-proton collisions.
title NNPDFpol2.0: a global determination of polarised PDFs and their uncertainties at next-to-next-to-leading order
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
Nuclear Experiment
Nuclear Theory
url https://arxiv.org/abs/2503.11814