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arXiv · 2211.16485

Four-loop large-n_f contributions to the non-singlet structure functions F_2 and F_L

A. Basdew-Sharma·A. Pelloni·Franz Herzog·A. Vogt
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Abstract

We have calculated the n_f^2 and n_f^3 contributions to the flavour non-singlet structure functions F_2 and F_L in inclusive deep-inelastic scattering at the fourth order in the strong coupling alpha_s. The coefficient functions have been obtained by computing a very large number of Mellin-N moments using the method of differential equations, and then determining the analytic forms in N and Bjorken-x from these. Our new n_f^2 terms are numerically much larger than the n_f^3 leading large-nf parts which were already known; they agree with predictions of the threshold and high-energy resummations. Furthermore our calculation confirms the earlier determination of the four-loop n_f^2 part of the corresponding anomalous dimension. Via the no-pi^2 conjecture/theorem for Euclidean physical quantities, we predict the z4 n_f^3 part of the fifth-order anomalous dimension for the evolution of non-singlet quark distributions.

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A. Basdew-Sharma, A. Pelloni, Franz Herzog, A. Vogt. 2022-11-29. Four-loop large-n_f contributions to the non-singlet structure functions F_2 and F_L. https://doi.org/10.1007/jhep03(2023)183

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