Abstract
We present the Bjorken integral extracted from Jefferson Lab experiment EG1b for . The integral is fit to extract the twist-4 element which appears to be relatively large and negative. Systematic studies of this higher twist analysis establish its legitimacy at around . We also performed an isospin decomposition of the generalized forward spin polarizability . Although its isovector part provides a reliable test of the calculation techniques of chiral perturbation theory, our data disagree with the calculations.
- Received 21 February 2008
DOI:https://doi.org/10.1103/PhysRevD.78.032001
©2008 American Physical Society