Physics – Nuclear Physics – Nuclear Theory
Scientific paper
1997-12-10
Nucl.Phys.A635:497-508,1998
Physics
Nuclear Physics
Nuclear Theory
revtex, 17 pages, 3 ps figs included
Scientific paper
10.1016/S0375-9474(98)00202-4
We test the Gerasimov-Drell-Hearn (GDH) sum rule numerically by calculating the total photon absorption cross sections $\sigma_{1/2}$ and $\sigma_{3/2}$ on the nucleon via photon excitation of baryon resonances in the constituent quark model. A total of seventeen, low-lying, non-strange baryon resonances are included in this calculation. The transverse and longitudinal interference cross section, $\sigma_{1/2}^{TL}$, is found to play an important role in the study of the $Q^2$ variation of the sum rule. The results show that the GDH sum rule is saturated by these resonances at a confidence level of 94%. In particular, the $P_{33}(1232)$ excitation largely saturates the sum rule at $Q^2 = 0$, and dominates at small $Q^2$. The GDH integral has a strong $Q^2$-dependence below $Q^2= 1.0 {GeV}^2$ and changes its sign around $Q^2= 0.3 {GeV}^2$. It becomes weakly $Q^2$-dependent for $Q^2 > 1.0 {GeV}^2$ because of the quick decline of the resonance contributions. We point out that the $Q^2$ variation of the GDH sum rule is very important for understanding the nucleon spin structure in the non-perturbative QCD region.
Li Zhi Peng
Lu Ding H.
Ma Wen-Xiu
Thomas Anthony W.
No associations
LandOfFree
$Q^2$--Dependence of the Gerasimov-Drell-Hearn Sum Rule does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with $Q^2$--Dependence of the Gerasimov-Drell-Hearn Sum Rule, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and $Q^2$--Dependence of the Gerasimov-Drell-Hearn Sum Rule will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-437502