QCD Analysis of Polarized Deep Inelastic Scattering Data

TL;DR

This paper presents a next-to-leading order QCD analysis of polarized deep inelastic scattering data, deriving new parton distribution parameterizations, determining alpha_s, and exploring higher twist effects with implications for lattice QCD.

Contribution

It introduces updated polarized parton distribution functions and provides a precise alpha_s value, including the impact of scale variations and higher twist contributions.

Findings

Alpha_s(Mz^2) = 0.1132 with uncertainties

First moments of polarized distributions with error correlations

Higher twist contributions are compatible with zero

Abstract

A QCD analysis of the world data on polarized deep inelastic scattering is presented in next--to--leading order, including the heavy flavor Wilson coefficient in leading order in the fixed flavor number scheme. New parameterizations are derived for the quark and gluon distributions and the value of $\alpha_s(M_z^2)$ is determined. The impact of the variation of both the renormalization and factorization scales on the distributions and the value of $\alpha_s$ is studied. We obtain $\alpha_s^{\rm NLO}(M_Z^2) = 0.1132~~\begin{array}{l} + 0.0056 \\ -0.0095 \end{array}$. The first moments of the polarized twist--2 parton distribution functions are calculated with correlated errors to allow for comparisons with results from lattice QCD simulations. Potential higher twist contributions to the structure function $g_1(x,Q^2)$ are determined and found to be compatible with zero both for proton and deuteron targets.