Analytic and "frozen" QCD coupling constants up to NNLO from DIS data

TL;DR

This paper analyzes deep inelastic scattering data using modified QCD coupling constants that eliminate unphysical singularities, improving agreement with experimental results and confirming the behavior of higher twist terms at NNLO.

Contribution

It introduces analytic and frozen modifications of the QCD coupling constant up to NNLO and demonstrates their effectiveness in fitting DIS data without unphysical singularities.

Findings

Improved fit between theory and DIS data with modified coupling constants.

No unphysical Landau pole in the modified coupling constants.

Confirmation of higher twist behavior at NNLO.

Abstract

Deep inelastic scattering data on the F_2 structure function provided by the BCDMS, SLAC and NMC collaborations are analyzed in the non-singlet approximation with the analytic and "frozen" modifications of the strong coupling constant featuring no unphysical singularity (the Landau pole). Improvement of agreement between theory and experiment, with respect to the case of the standard perturbative definition of alpha_s considered recently, is observed and the behavior of the higher twist terms in the next-to-next-to-leading-order is found to be confirming earlier studies on the subject.