Experimental determination of the evolution of the Bjorken integral at low Q^2

TL;DR

This study measures the Bjorken integral at low Q^2 to connect hadronic and partonic nucleon descriptions, providing new insights into nucleon structure and extracting the twist-4 matrix element.

Contribution

It provides the first experimental determination of the Bjorken integral in the low Q^2 resonance region and combines it with higher Q^2 data to extract the twist-4 matrix element.

Findings

Bjorken integral measured at 0.17 < Q^2 < 1.10 GeV^2

Data bridge hadronic and partonic descriptions of the nucleon

Extraction of the non-singlet twist-4 matrix element f_2

Abstract

We extract the Bjorken integral Gamma^{p-n}_1 in the range 0.17 < Q^2 < 1.10 GeV^2 from inclusive scattering of polarized electrons by polarized protons, deuterons and 3He, for the region in which the integral is dominated by nucleon resonances. These data bridge the domains of the hadronic and partonic descriptions of the nucleon. In combination with earlier measurements at higher Q^2, we extract the non-singlet twist-4 matrix element f_2.