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arXiv · 2306.15294

DGLAP evolution of parton distributions at approximate N$^3$LO

Felix Hekhorn·Giacomo Magni
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Abstract

We present recent progress towards a global determination of parton distribution functions (PDFs) at approximate N$^3$LO (aN$^3$LO) accuracy within the NNPDF framework. We construct a parametrisation of the $\mathcal{O}(\alpha_s^4)$ QCD splitting functions and anomalous dimensions reproducing all known exact results, estimate the associated missing and incomplete higher order uncertainties (MHOU and IHOU, respectively), and implement it in the open-source DGLAP code EKO enabling PDFs to be evolved at aN$^3$LO accuracy in the NNPDF fitting framework. We compare aN$^3$LO calculation of splitting functions with the results of lower perturbative orders and quantify the impact of the various sources of theoretical uncertainties.

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Felix Hekhorn, Giacomo Magni. 2023-06-27. DGLAP evolution of parton distributions at approximate N$^3$LO. https://arxiv.org/abs/2306.15294

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