DOI: 10.1140/epjc/s2002-01041-2
Spin structure function g1(x,Q2) and the DHGHY integral I(Q2) at low Q2: predictions from the GVMD model
B. Badelek1, 2, J. Kwiecinski3 and B. Ziaja3, 4, 51 Institute of Experimental Physics, Warsaw University, Hoza 69, 00-681 Warsaw, Poland
2 Department of Physics, Uppsala University, P.O. Box 530, 751 21 Uppsala, Sweden
3 Department of Theoretical Physics, H. Niewodniczanski Institute of Nuclear Physics, Radzikowskiego 152, 31-342 Cracow, Poland
4 Department of Biochemistry, BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
5 High Energy Physics, Uppsala University, P.O. Box 535, 751 21 Uppsala, Sweden
(Received: 9 July 2002 / Published online: 7 October 2002 )
Abstract
Theoretical predictions for the polarized nucleon structure function
g1(x,Q2)
at low
Q2 are obtained in the framework of the generalized
vector meson dominance model. Contributions from both light and
heavy
vector mesons are evaluated. In the
photoproduction limit the first moment of
g1
is related to the static properties of the nucleon via the
Drell-Hearn-Gerasimov-Hosoda-Yamamoto sum rule.
This property is employed to fix the magnitude of the light vector
meson
contribution to
g1, using the recent measurements in the region
of baryonic resonances. The results are compared to the data
on
g1(x,Q2).
Finally, the DHGHY moment function
I(Q2) is calculated, and
our theoretical
predictions are confronted with the recent preliminary data obtained
at the
Jefferson Laboratory.
© Società Italiana di Fisica, Springer-Verlag 2002
