Experimental determination of the evolution of the Bjorken integral at low Q2

Phys Rev Lett. 2004 Nov 19;93(21):212001. doi: 10.1103/PhysRevLett.93.212001. Epub 2004 Nov 15.

Abstract

We extract the Bjorken integral Gamma1(p-n) in the range 0.17 < Q2 < 1.10 GeV2 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 Q2, we extract the nonsinglet twist-4 matrix element f2.