Determination of the Bjorken sum and strong coupling from polarized structure functions
Abstract
We present an NLO perturbative analysis of all available data on the polarized structure function g_{1} ( x, Q^{2}) with the aim of making a quantitative test of the validity of the Bjorken sum rule, of measuring α_{s} and of deriving helicity fractions. We take particular care over the small x extrapolation, since it is now known that Regge behaviour is unreliable at perturbative scales. For fixed α_{5}, we find that if all the most recent data are included g_{A} = 1.19 ± 0.09, confirming the Bjorken sum rule at the 8% level. We further show that the value of α_{s} is now reasonably well constrained by scaling violations in the structure function data, despite the fact that it cannot yet be reliably fixed by the value of the Bjorken sum: our final result is a_{s}( m_{z}) = _{0.008}^{+0.010}. We also confirm earlier indications of a sizeable positive gluon polarization in the nucleon.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1997
 DOI:
 10.1016/S05503213(97)002010
 arXiv:
 arXiv:hepph/9701289
 Bibcode:
 1997NuPhB.496..337A
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 24 pages, 9 figures, plain LaTeX with epsfig. Final version, to be published in Nucl. Phys. B. Several typos corrected