Sign change of the moment at n=0 of the polarized structure function gp1
Abstract
The sum rule for the structure function gp1 which is related to the cross section of photoproduction is used to show that a sign change of the integral corresponding to the appropriately defined moment at n=0 where the integral is cut at the point x=xc(Q2) occurs at very small Q2 near Q2~0.09 (GeV/c)2 and xc~0.024. This fact shows that the origin of the sign difference between the Ellis-Jaffe sum rule and the Drell-Hearn-Gerasimov sum rule lies in the rapid change of the elastic contribution at low Q2 which is compensated by the inelastic contribution to satisfy the sum rule at n=0. Hence it occurs at very small Q2.
- Publication:
-
Physical Review C
- Pub Date:
- October 2005
- DOI:
- arXiv:
- arXiv:hep-ph/0510155
- Bibcode:
- 2005PhRvC..72d5205K
- Keywords:
-
- 24.85.+p;
- 11.55.Hx;
- 13.60.Hb;
- 24.70.+s;
- Quarks gluons and QCD in nuclei and nuclear processes;
- Sum rules;
- Total and inclusive cross sections;
- Polarization phenomena in reactions;
- High Energy Physics - Phenomenology;
- Nuclear Theory
- E-Print:
- Eq.(14) is corrected. Though the effect of this correction is very small,Figs.1 and 2 are replaced