On γ₅ in higher-order QCD calculations and the NNLO evolution of the polarized valence distribution

Moch, S, Vermaseren, JAM and Vogt, A (2015) On γ₅ in higher-order QCD calculations and the NNLO evolution of the polarized valence distribution. PHYSICS LETTERS B, 748. pp. 432-438.

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	Text 1506.04517v1.pdf - Author Accepted Manuscript Download (135kB)

Abstract

We discuss the prescription for the Dirac matrix gamma_5 in dimensional regularization used in most second- and third-order QCD calculations of collider cross sections. We provide an alternative implementation of this approach that avoids the use of an explicit form of gamma_5 and of its (anti-) commutation relations in the most important case of no more than one gamma_5 in each fermion trace. This treatment is checked by computing the third-order corrections to the structure functions F_2 and g_1 in charged-current deep-inelastic scattering with axial-vector couplings to the W-bosons. We derive the so far unknown third-order helicity-difference splitting function Delta P_ns^(2)s that contributes to the next-to-next-to-leading order (NNLO) evolution of the polarized valence quark distribution of the nucleon. This function is negligible at momentum fractions x >~ 0.3 but relevant at x << 1.

Item Type:	Article
Additional Information:	11 pages, Latex, 2 figures. FORM and Fortran files of the main results available with the source
Uncontrolled Keywords:	hep-ph, hep-ph
Depositing User:	Symplectic Admin
Date Deposited:	10 Oct 2017 13:35
Last Modified:	05 Oct 2023 09:26
DOI:	10.1016/j.physletb.2015.07.027
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3009933