Determination of alpha_s from scaling violations of truncated moments of structure functions

TL;DR

This study addresses the precision extraction of the QCD coupling $\alpha_s(M_Z)$ from scaling violations in deep inelastic scattering by circumventing biases from parton parametrizations. It combines truncated Mellin moments of the nonsinglet structure function $F_2^{NS}$ with a neural-network representation of $F_2$ to preserve full experimental error information and correlations, enabling a bias-free determination of $\alpha_s$ from scaling violations. The authors obtain $\alpha_S(M_Z)=0.124^{+0.004}_{-0.007}$ (exp) $^{+0.003}_{-0.004}$ (th) = $0.124^{+0.005}_{-0.008}$ (total), with theoretical uncertainties well controlled and the dominant error coming from statistics. The work demonstrates a powerful approach that integrates evolution of truncated moments with a probabilistic, data-driven description of structure functions, offering a template for future high-precision extractions and potential soft-gluon resummation refinements. Overall, the paper provides a bias-minimized, methodologically rigorous path to extracting fundamental QCD parameters from DIS data.

Abstract

We determine the strong coupling alpha_s(M_Z) from scaling violations of truncated moments of the nonsinglet deep inelastic structure function F_2. Truncated moments are determined from BCDMS and NMC data using a neural network parametrization which retains the full experimental information on errors and correlations. Our method minimizes all sources of theoretical uncertainty and bias which characterize extractions of alpha_s from scaling violations. We obtain alpha_s(M_Z) = 0.124 +0.004-0.007 (exp.) + 0.003- 0.004 (th.).

Figures (4)

• Figure 1: NMC and BCDMS kinematic range.
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